                  UNITED STATES COURT OF APPEALS

                      FOR THE FIRST CIRCUIT

                                           

No. 92-2242

                   CAMBRIDGE PLATING CO., INC.,

                      Plaintiff, Appellant,

                                v.

                           NAPCO, INC.,

                       Defendant, Appellee.

                                           

           APPEAL FROM THE UNITED STATES DISTRICT COURT

                FOR THE DISTRICT OF MASSACHUSETTS

         [Hon. Douglas P. Woodlock, U.S. District Judge]
                                                       

                                           

                              Before

                     Torruella, Circuit Judge,
                                             
                  Coffin, Senior Circuit Judge,
                                              
                   and Boudin, Circuit Judge. 
                                            

                                           

  Thomas K. Christo with whom David  B. Chaffin, Joseph M.  Kaigler,
                                                                   
and Hare &amp; Chaffin were on brief for appellant.
                
  Richard  L. Burpee with whom William A. McCormack was on brief for
                                                   
appellee.

                                           

                          April 22, 1993
                                           

     COFFIN, Senior  Circuit Judge.  Plaintiff  Cambridge Plating
                                  

Company  filed  this  lawsuit  against  defendant  Napco  seeking

damages  for  a  defective  wastewater  treatment  system.    The

district court granted summary  judgment for Napco, concluding as

a  matter of  law that  the statutes  of limitations  had run  on

plaintiff's claims.  On appeal, Cambridge Plating argues that the

court  should have  let the  jury decide  whether Massachusetts's

"discovery" rule  suspended the running of  the limitations clock

long  enough to  preserve  its claims.    Because we  agree  with

plaintiff  that material  issues of fact  remain, we  reverse the

summary judgment.

                                I.

A. Factual Background
                     

     Cambridge   Plating  is  an   electroplating  business  that

discharges wastewater containing  various metal contaminants into

municipal  sewers.   In  an effort  to meet  strict environmental

regulations  governing such discharges,  the company commissioned

the design and installation of a wastewater treatment system from

defendant  Napco.  The contract  price for the  system was nearly

$400,000.    Cambridge   Plating  additionally  needed   to  make

substantial changes  to its facility to  accommodate the enormous

and  complex  array of  pipes,  tanks,  valves, mixers,  sensors,

recorders  and other apparatus,  pushing the  total cost  for the

project to $2.8 million.

     The system began running on October 30, 1984, but it was not

then  fully operational,  and  Napco continued  installation  and

                               -2-

debugging for  another year.  In October  1985, Cambridge Plating

began to experience unsatisfactory results; testing revealed that

contaminant  levels   in  the  wastewater   discharges  sometimes

exceeded  regulatory  limits.     Cambridge  Plating's   managers

believed the problems stemmed from errors by the system operators

or  errors in  wastewater sampling.   This  belief was  fueled by

Napco representatives who, when contacted by Cambridge Plating on

a number of occasions between early 1986 and 1988, suggested ways

that Cambridge Plating could change  its operation of the system.

Napco refused further visits to Cambridge Plating to service  the

system unless it was paid $1,000 per day.

     Cambridge  Plating   took  several  steps   to  resolve  the

perceived  operational or  sampling  problems.   It replaced  the

system operators and implemented  the changes suggested by Napco.

In late  1986, the company  asked a wastewater  treatment expert,

Patrick Hunt, to evaluate the system  and the company's operation

of  it.  Although Hunt found  some minor problems with the system

itself, most of his  recommendations were operational.  Cambridge

Plating  adopted  his  suggestions,  but  the  company  continued

periodicaly to exceed lawful contaminant levels.

     On  December  29,  1988, the  Massachusetts  Water Resources

Authority (MWRA), the agency responsible for effluent regulation,

assessed  a   penalty  of  $682,250  on   Cambridge  Plating  for

violations during  1986-88.  In February  1989, Cambridge Plating

commissioned  another  expert,  Peter  Moleux,  to  evaluate  the

system.   Moleux's  lengthy  inspection, which  included a  close

                               -3-

comparison  of Napco's  written materials with  the system  as it

actually existed, revealed design flaws, failure to install parts

specified in the  plans, and  substandard engineering  practices.

Most significantly,  Moleux discovered  that Napco had  failed to

install  an important component,  a static  mixer, inside  a pipe

where system schematics  provided by Napco  indicated erroneously

the  device  had  been placed.    Omission  of  the static  mixer

rendered the  system incapable of adequately  cleaning 80 percent

of the wastewater.

     After  Moleux's  evaluation, Cambridge  Plating  installed a

static  mixer  at the  point called  for by  Napco's plans.   The

system  thereafter worked  properly,  enabling Cambridge  Plating

consistently to comply with the effluent limitations.

     B. Procedural Background
                             

     Cambridge Plating  filed this action in  June 1990, alleging

causes  of  action for  breach  of  contract, negligence,  fraud,

negligent  misrepresentation, and violation  of the Massachusetts

unfair  business practices  act, Mass.  Gen. Laws  Ann. ch.  93A.

Napco moved  for summary judgment, arguing that  all of Cambridge

Plating's  claims  were  barred  by the  applicable  statutes  of

limitation.  The district court agreed with Napco.

     The court concluded that Cambridge Plating's purchase of the

wastewater treatment system  was a  sale of goods,  and that  its

contract  claim thus  was governed  by the  four-year limitations

period under the  Uniform Commercial Code,  Mass. Gen. Laws  Ann.

ch. 106,   2-725, rather than by the general six-year contractual

                               -4-

limitations period,  Mass. Gen. Laws Ann.  ch. 260,   2.   All of

Cambridge Plating's causes of  action, therefore, were subject to

either  three-  or  four-year  statutes of  limitation.1    These

claims  were  time-barred,  the  court  determined, because  they

accrued in late 1985,  some four and one-half years  before suit,

when the company  learned that  the system was  failing to  bring

effluent  discharges within  legal  limits.   The court  rejected

plaintiff's  argument that  the limitations  periods were  tolled

until Moleux's  evaluation, when Cambridge Plating  first learned

the  cause of the system's  problems.  The  court concluded that,

with  reasonable   diligence,   Cambridge  Plating   could   have

discovered the defects once the system started malfunctioning.

     On   appeal,  Cambridge   Plating  argues  that   the  court

misconstrued the contract and the discovery rule, which serves to

toll certain  hard-to-discern claims, and improperly  usurped the

jury's role when it decided as a matter of law that  the rule did

not  preserve the company's claims.   Our review  of the district

court's grant of  summary judgment  is plenary, and  we read  the

record in the light most amicable to the party contesting summary

judgment.  See,  e.g., Pagano v.  Frank, 983 F.2d  343, 347  (1st
                                       

Cir. 1993).

                               II.

                    

     1  Tort  actions are  subject  to  a three-year  limitations
period, Mass.  Gen. Laws  Ann.  ch. 260,    2A,  and a  four-year
statute  applies to  consumer  protection actions  brought  under
Chapter 93A, Mass. Gen. Laws Ann. ch. 260,   5A.

                               -5-

     Cambridge Plating contends that  the district court erred in

ruling as a matter of law that the contract with Napco was a sale

of  goods contract  within  the  scope  of  the  UCC.    Although

determining the type of contract at issue typically may be a jury

function, see United States v. City  of Twin Falls, 806 F.2d 862,
                                                  

870 (9th Cir. 1986),  we believe the facts here  are sufficiently

clear and undisputed  that the  district court  was permitted  to

make its finding as a matter of law.  Id.
                                         

     Cambridge  Plating  asserts  that the  UCC  is  inapplicable

because  the  equipment it  purchased  does not  meet  the Code's

definition of goods.  Under the UCC,  "goods" are defined as "all

things . .  . which are movable at the  time of identification to

the contract for sale . . . ."  See Mass. Gen. Laws Ann. ch. 106,
                                   

   2-105.   The  company  emphasizes  the  immense  size  of  the

wastewater  treatment   system  and  its  integration   into  the

electroplating  facility in  an effort  to equate  this situation

with White v. Peabody  Construction Co., 386 Mass. 121,  132, 434
                                       

N.E.2d 1015 (1982), where the  court ruled that the UCC  does not

apply to "the sale of structures attached to realty."

     But this comparison  is flawed.   The claims  in White  were
                                                           

based on contracts calling for "[t]he erection of  buildings" and

for the sale  of a completed building  -- "not contracts for  the

sale of bricks or  window frames or  caulking material."  Id.  at
                                                             

131, 133.  In this case, the proposal specified the components of

the  system as  the  primary subject  of  the sale  and,  indeed,

specifically described the contract as one "for goods."  See App.
                                                            

                               -6-

at  113.  The proposal separately listed eighty-eight items to be

provided  by  Napco,  eighty-two  of  which  involved  pieces  of

equipment.   At the time of identification to the contract, these

were movable and  therefore goods  within the scope  of the  UCC.

Accord Twin  Falls,  806 F.2d  at 871  (components of  wastewater
                  

treatment  system   are  movable  goods).    It  was  only  after

installation  into  plaintiff's  building that  the  items became

merged with the  facility and  hence unmovable --  to borrow  the

district  court's analogy, like cans  of paint sold  as goods and

then applied to a wall.2

     That the  contract involved the purchase  of engineering and

installation services, in  addition to a sale of  goods, is of no

consequence.   In our view,  Massachusetts law is consistent with

the general trend to view such mixed contracts as governed by the

UCC.  See Twin  Falls, 806 F.2d at 871.   In White, 386  Mass. at
                                                  

131-32, the Supreme Judicial  Court ruled that "[c]ontracts whose

predominant  factor,  thrust,  or  purpose is  the  rendition  of

services"  are  outside  the  scope  of  the  UCC.    It  follows

inexorably that, if  the "rendition  of services" is  not at  the

heart of a mixed contract, the UCC does govern.  See USM Corp. v.
                                                              

                    

     2 Plaintiff also  cites in support of its  position Chestnut
                                                                 
Hill  Dev. Corp. v. Otis Elevator Co.,  653 F. Supp. 927, 932 (D.
                                     
Mass.  1987), which  held that  structures "attached  to realty,"
such  as  the elevator  system at  issue  there, are  not "goods"
within  the meaning  of the  UCC.   Under  the UCC,  however, the
inquiry  centers  on the  nature of  the  goods "at  the  time of
identification  to the contract," Mass. Gen. Laws Ann. ch. 106,  
2-105.  It is beyond debate that the contract here listed movable
items.  See  Burnham v. Mark IV Homes, Inc.,  387 Mass. 575, 581,
                                           
441 N.E.2d 1027 (1982) (modular homes are "goods" within coverage
of UCC).

                               -7-

Arthur  D.  Little Systems,  Inc., 28  Mass.  App. 108,  119, 546
                                 

N.E.2d 888  (1989) (contract  for computer system  involving both

sale of goods and delivery of services governed by UCC).

     The  undisputed  facts  demonstrate  that  the deal  between

Cambridge  Plating and Napco was  first, and foremost,  a sale of

goods.    Most of  the purchase  price  was for  the specifically

listed  items of equipment.   Only $68,970 of  the total contract

price  of   $398,200  was   for  installation,3   and  purchasing

installation  from  Napco  was  even  optional.    See  generally
                                                                 

Chestnut Hill Dev.  Corp. v. Otis Elevator Co., 653 F. Supp. 927,
                                              

932  (D.  Mass.   1987)  (a  contract  to   supply  "hundreds  of

components"  is not "one whose primary thrust is the rendition of

services").  Because  the contract was so heavily weighted toward

goods, it must fall within the scope of the UCC.

     The district court correctly  applied the UCC to plaintiff's

contract claim.   We thus  move on  to consider whether  this and

Cambridge Plating's other claims were timely brought.

                               III.

     Although  the  Massachusetts legislature  has  set statutory

limitations periods for various causes of action, see supra at 4-
                                                           

5  &amp;  n.1, determining  when claims  accrue  "`has long  been the

product  of judicial  interpretation,'"  Hoult v.  Hoult, 792  F.
                                                        

Supp. 143, 144 (D.  Mass. 1992) (quoting Franklin v.  Albert, 381
                                                            

                    

     3  The  cost of  engineering  services  to assist  Cambridge
Plating with preparing its  local industrial discharge permit and
meeting with  local officials -- a single item among a list of 83
-- also was included in the equipment subtotal.

                               -8-

Mass. 611, 617, 411 N.E.2d 458 (1980)).  Caselaw establishes that

the  general  rule for  negligence claims  is  that the  cause of

action  accrues at the  time of injury.   Riley  v. Presnell, 409
                                                            

Mass. 239,  243, 565 N.E.2d  780 (1991).   Similarly, a cause  of

action for breach of contract usually  accrues at the time of the

breach,  International Mobiles Corp. v. Corroon &amp; Black/Fairfield
                                                                 

&amp; Ellis, Inc., 29 Mass. App. 215, 221, 560 N.E.2d 122 (1990), and
             

accrual  of  a chapter  93A claim  typically  occurs at  the time

injury  results from the assertedly unfair or deceptive acts.  29

Mass. App. at 220-21.

     These designated  times  are subject  to  some  flexibility,

however,  because Massachusetts  courts  have recognized  that it

would  be  unfair to  begin  running the  statute  of limitations

before a plaintiff is  put on notice that  she has a claim.   See
                                                                 

Bowen v.  Eli Lilly  &amp; Co.,  408 Mass. 204,  205, 557  N.E.2d 739
                          

(1990); Anthony's Pier Four, Inc. v. Crandall Dry Dock Engineers,
                                                                 

Inc.,  396 Mass. 818, 824,  489 N.E.2d 172  (1986); Franklin, 381
                                                            

Mass at 619.   The judicially created tool for  ensuring fairness

is the  "discovery rule," which provides that,  regardless of the

actual  time of  breach or injury,  "a cause  of action  does not

accrue  until a  plaintiff discovers,  or reasonably  should have

discovered, that she  may have been  injured as  a result of  the

defendant's conduct."   Hoult,  792 F. Supp.  at 144.   See  also
                                                                 

Riley,  409 Mass. at 244; Bowen, 408 Mass. at 205-06; Hendrickson
                                                                 

v. Sears,  365  Mass. 83,  83-84,  310 N.E.2d  131 (1974).    The
        

delayed  knowledge may be either the fact of injury, such as when

                               -9-

an item is not used and thus not discovered to be defective for a

substantial time  after its  purchase, see, e.g.,  Anthony's Pier
                                                                 

Four, Inc., 396 Mass. at 825-26,4  or the cause of the harm, such
          

as when an individual  with a physical illness does  not discover

the illness's  link to  particular medical treatment  until years

after becoming sick, see, e.g., Bowen, 408 Mass. at 207.5
                                     

     Not all  contractual causes  of action in  Massachusetts are

governed  by  the  judicially  crafted  accrual  rules.    Claims

alleging breach  of a contract for the  sale of goods instead are

subject to the detailed provisions of the UCC.  Under   2-275(2),

a  cause of  action  for breach  of  a sales  contract  generally

accrues  when the  breach  occurs, "regardless  of the  aggrieved

party's  lack  of  knowledge of  the  breach,"  and  a breach  of

warranty occurs when tender of delivery is made.  Mass. Gen. Laws

Ann.  ch. 106,     2-275(2).   When  a seller  gives  an explicit

warranty of future performance, however,

                    

     4  Anthony's  Pier Four  involved  an action  filed  in 1980
                            
against  the designers  of a  ship mooring  system that  had been
completed in 1968.  The plaintiff claimed that it was  unaware of
the system's design deficiencies  until it actually failed during
a storm  in 1978.   The  court held that  the lawsuit  was timely
because  "[t]he plaintiff  discovered  the breach  when the  boat
capsized in 1978  and there  is no  showing that  it should  have
known of the breach earlier." 396 Mass. at 826.

     5 The plaintiff  in Bowen had  suffered a malignant  vaginal
                              
tumor requiring surgery in 1969 but did not file suit blaming the
cancer on a prescription drug manufactured by defendant Eli Lilly
&amp;  Co. until 1983.   The  court applied  the discovery  rule, but
nevertheless determined that the plaintiff was on notice that the
defendant may have caused  her harm more than three  years before
filing her action.  408 Mass. at 210. 

                               -10-

     and discovery of the breach must await the time of such
     performance the cause of action accrues when the breach
     is or should have been discovered.

Id.  Thus, like the tort and contract causes of action subject to
   

the  judicial discovery rule, a  cause of action  for breach of a

warranty of future performance is tolled until  the plaintiff has

adequate notice of the claim.

     The district court found that the  transaction at issue here

was  a sale  of goods,  and that  the UCC  therefore governs  the

contract claim.   It further determined that  Napco expressly had

warranted  the  future performance  of  the  wastewater treatment

system, and that, consequently, the statutory discovery provision

applies.   Because  we  have concluded  that  the district  court

correctly ruled as a  matter of law that the parties entered into

a sale  of goods, and there  is no challenge to  its finding that

Napco  gave  an  explicit  warranty of  future  performance,  the

timeliness  of  all  of  plaintiff's  claims  is  linked  to  the

discovery rule.    

                               IV.

     Our  analysis of  the discovery rule's  impact in  this case

must  begin with the parties'  conflicting views on  how the rule

operates.   Defendant Napco asserts that the rule applies only to

"inherently unknowable"  causes of  action and that  the question

before us is whether Cambridge Plating's claims were discoverable

through  reasonably  diligent  efforts.6   If  Cambridge  Plating

                    

     6  Although  the  dictionary  definition  suggests  that  an
"inherently" unknowable  claim is  one that would  be permanently
                                                                 
undiscoverable, see  The Random  House Dictionary of  the English
                                                                 

                               -11-

could  have  discovered  its claims  earlier  through  reasonable
     

diligence,  Napco  maintains,  then   they  were  not  inherently
                                                                 

unknowable and the discovery rule would not apply.

     Cambridge Plating  counters  that the  applicability of  the

discovery rule does not depend on whether it was possible for the

company  to  discover  Napco's  responsibility  for  the  defects

earlier  by pursuing some other reasonable course of action.  The

inquiry, it asserts, must focus on the reasonableness of what the

company actually did.  If the company acted diligently, but still

reasonably  failed to learn of its cause of action, the discovery

rule would continue to delay the limitations clock.

     The  district  court  adopted  Napco's  view,  finding  that

Cambridge Plating could have discovered the system's defects once

the  company  learned  that  the water  treatment  equipment  was

failing to  bring effluent discharges  within legal limits.   The

court pointed to expert Moleux's affidavit  as evidence that "the

defects were manifestly knowable to someone with an appropriately
                                

trained eye," Opinion at 10  (emphasis in original).  It  did not

matter, the court ruled,  whether Cambridge Plating had exercised

reasonable  diligence in  hiring the  first expert,  who did  not

discover  the   defects:  "[w]hether   a  defect  is   inherently

unknowable turns  not upon  an inquiry  into whether the  injured

                    

Language (2d  ed. 1987)  at  982, the  phrase  has been  used  to
        
describe  a cause of action  that was incapable  of detection for
some  prolonged  period  of  time   even  with  the  exercise  of
reasonable diligence.  See,  e.g., Tagliente v. Himmer,  949 F.2d
                                                      
1,  5 (1st  Cir. 1991);  White v.  Peabody Construction  Co., 386
                                                            
Mass. 121, 129  (1982); International Mobiles Corp. v.  Corroon &amp;
                                                                 
Black/Fairfield &amp; Ellis, Inc., 29 Mass. App. 215, 222 (1990). 
                             

                               -12-

party did in fact exercise reasonable diligence, but instead upon
                 

an inquiry  into whether reasonable  diligence could have  led to
                                                    

discovery  of the defects," id. at 11 n.5 (emphasis in original).
                               

This implies  that at least  two courses of  action would meet  a

standard  of reasonable diligence  -- one pursued  by the injured

party and another that could have been pursued.

     We are  persuaded that Cambridge Plating's  statement of the

discovery   rule   is   the  one   consistent   with   prevailing

Massachusetts law.   The rule is designed  to protect plaintiffs,

to assure that "`a plaintiff [] be put on notice before his claim

is barred,'" Anthony's Pier Four, Inc., 396 Mass. at 824 (quoting
                                      

Franklin, 381 Mass. at 619).  This protection would be frustrated
        

if  a  plaintiff who  remained unaware  of  his claim  even after

conducting reasonable inquiry was  time-barred from pursuing  it.

Fairness  dictates   that  the  discovery  rule   not  be  deemed

inapplicable simply  because reasonable actions other  than those

taken by the plaintiff  could have uncovered the injury  or cause
                             

of harm.  See  generally Franklin, 381 Mass. at  618 (limitations
                                 

statutes are intended, inter alia, to "`stimulate [plaintiffs] to
                                 

activity'" and  "punish[]  negligent  delay")  (quoting  Wood  v.
                                                             

Carpenter, 101 U.S. 135, 139 (1879)).
         

     Indeed, the contrary conclusion would require something more

than  reasonableness  on the  part  of  the plaintiff;  Cambridge

Plating complains  that nothing  less than omniscience  would do.

Whenever more than  one reasonable  option for  pursuing a  claim

existed -- when, for example, two or three qualified experts were

                               -13-

available to  investigate a non-performing piece  of equipment --

the  plaintiff would  be  penalized if  the  first expert  chosen

reasonably failed to discover a problem the second expert managed

to  detect.  That the  plaintiff had been  diligent in hiring the

first expert would be  irrelevant, even though the very  point of

the rule was to protect plaintiffs whose reasonable efforts would

fail  to put  them on notice  of their claims.   This, certainly,

cannot be the intent of the Massachusetts courts.

     The   formulation  that   we  believe   reflects  prevailing

Massachusetts law was particularly well articulated in Bowen, one
                                                            

of the Supreme Judicial Court's more recent discovery rule cases:

     This  rule  prescribes  as  crucial  the  date  when  a
     plaintiff  discovers,  or  any earlier  date  when  she
     should  reasonably have  discovered, that she  has been
     harmed  or  may have  been  harmed  by the  defendant's
     conduct.
     . . .
     [T]he  statute of  limitations  starts to  run when  an
     event  or events  have  occurred that  were  reasonably
     likely to put the plaintiff on  notice that someone may
     have caused her injury.

408  Mass. at 205-206, 207.  See  also, e.g., Riley, 409 Mass. at
                                                   

243; Franklin, 381 Mass. at  619.  Bowen makes it clear  that the
                                        

steps taken by a plaintiff to discover her cause of action play a

role  in the decision whether  to apply the  discovery rule: "the

decision  whether  any  [injury]  should  reasonably   have  been

uncovered  ha[s] to be made  in light of  what reasonable inquiry

would have disclosed."  Id. at 206 (citing Friedman, 371 Mass. at
                                                   

485-86).  Accrual of  the plaintiff's cause of action  is tested,

therefore, "by  what a reasonable  person in  her position  would

                               -14-

have known or  on inquiry  would have discovered  at the  various

relevant times," Bowen, 408 Mass. at 210.
                      

     Thus, if Cambridge Plating acted  reasonably diligently when

it  hired the first expert,  the fact that  that expert failed to

discover the  system's  defects must  be sufficient  to toll  the

statute  of limitations.7    This is  so  because, if  reasonable

inquiry  failed to disclose the  problem, it cannot  be said that

the problem  "should reasonably have been  uncovered," Bowen, 408
                                                            

Mass. at 206.8

     We recognize that the district  court's interpretation finds

literal  support  in the  language of  a  number of  cases, which

describe  the discovery  rule as  applicable only  to "inherently

unknowable"  claims or refer to the time when a plaintiff "could"

have known of his claim.   See, e.g., Melrose Hous. Auth.  v. New
                                                                 

Hampshire  Ins. Co.,  402 Mass.  27, 34,  520 N.E.2d  493 (1988);
                   

Anthony's  Pier Four, Inc., 396  Mass. at 825-26  n.9; White, 386
                                                            

Mass.  at 129-30; International  Mobiles Corp., 29  Mass. App. at
                                              

                    

     7  We presume  here that  the expert  performed competently.
See infra p.17.
         

     8  The district  court's  decision may  reflect an  implicit
finding  that the  first  expert's efforts  were inadequate.   If
Moleux's  exhaustive study of the  system would have  met but not
surpassed the  threshold standard of reasonableness  even if done
two years  earlier, then  Hunt's apparently less  thorough review
would not have been sufficient inquiry under  the discovery rule.
On  the other  hand,  if Cambridge  Plating exercised  reasonable
diligence in hiring Hunt, and his performance was competent, then
Moleux's efforts beyond the  reasonableness threshold should  not
furnish a basis for  denying discovery rule protection.   On this
record, we do not  think that the district court  could determine
as a matter  of law  that the first  evaluation was  incompetent.
See Section V infra.     
                   

                               -15-

222; Melrose Hous. Auth. v. New Hampshire Ins. Co., 24 Mass. App.
                                                  

207, 212,  507 N.E.2d  787 (1987).   But  this support erodes  on

analysis.

     The two cases cited  by the district court as  precedent for

the standard it applied also refer to the "reasonably should have
                                                            

known"  formulation, see White, 386  Mass. at 129  &amp; 130; Melrose
                                                                 

Hous. Auth., 24  Mass. App. at  212, as do  other cases cited  by
           

Napco,  see, e.g., Anthony's Pier Four, Inc., 396 Mass. at 825-26
                                            

&amp;  n.9;  International  Mobiles, 29  Mass.  App.  at  218 &amp;  222.
                               

Moreover,  none  of  these  cases  involved  a  plaintiff  in the

position  Cambridge Plating claims to  be in here,  i.e., one who

acted diligently, yet still failed to learn of a cause of action.

     These  cases, instead, uniformly involve plaintiffs who were

not diligent,  and  that circumstance,  we believe,  has led  the
   

courts  to describe the rule  imprecisely.  When  a plaintiff has

made no reasonable  efforts to  discover the harm  or its  cause,

considering whether a plaintiff reasonably should have discovered
                                                 

his  claim will produce the same result as considering whether he

reasonably could have  discovered it.   For example,  if a  court
                

found that  a claim  could not  be discovered  through reasonable
                              

diligence,  it  would be  precluding as  well  a finding  that he

reasonably  should have  discovered it.   See,  e.g.,  White, 386
                                                            

Mass.  at 130  (in cases  cited, "the  nature of  the defendant's

wrong was such that  the plaintiff did not discover and could not

reasonably  have discovered that he or she had been injured until

[a later time]").

                               -16-

     Similarly,  a court  might find that,  if the  plaintiff had

been  diligent, she could have  discovered her claim.   From this
                         

conclusion, lacking  contrary information, it also  is logical to

presume  that the  plaintiff  should have  discovered her  claim.
                                    

Having  failed to act, the  plaintiff has no  basis for disputing

the  court's sensible  presumption that reasonable  actions would

have produced results.   See,  e.g., Friedman  v. Jablonski,  371
                                                           

Mass. 482, 486, 358 N.E.2d 994  (1976); Melrose, 24 Mass. App. at
                                               

212-215; Graveline  v. BayBank  Valley Trust  Co., 19  Mass. App.
                                                 

253,  254-55,  473  N.E.2d  700  (1985).    "Could"  and "should"

effectively are interchangeable in  this context, and the courts'

particular usage is of no significance.  

     Only when a plaintiff  has done what he  is supposed to  do,

and still  comes  up empty,  is  a court  faced with  a  possible

disjunction between  what he theoretically could have known if he
                                                

had chosen a different  reasonable path, and what he  should have
                                                            

known based on the reasonable inquiry he did make.   Because none

of  the cases  cited to  us present  that situation,  and because

construing the rule as the district court applied it  effectively

would  take away the protection the discovery rule is designed to

provide, we  are confident that  Cambridge Plating's view  of the

discovery rule is correct.

     We think it worth emphasizing  that, so construed, the  rule

does   not  permit  a  plaintiff  to  buy  time  by  engaging  an

incompetent "expert."  Hiring an individual  who is poorly suited

to  investigate the type of  injury suffered by  the plaintiff is

                               -17-

unlikely to be deemed  "reasonable" inquiry sufficient to suspend

the  limitations  period.     Moreover,  even  if  the  plaintiff

reasonably hires a professional he believes to be  competent, but

who fails to  discover a  defect that a  qualified expert  easily

should  have found, the plaintiff's only recourse is likely to be

against the deficient professional.  The discovery rule would not

save the overlooked claim  because reasonable inquiry should have
                                                            

put the  plaintiff on notice of  it.  See Friedman,  371 Mass. at
                                                  

486 &amp; n.4  (a competent lawyer  would have done title  search and

should have discovered defect). 

     The discovery rule's protection is limited in another way as

well.  The  rule does not suspend the  running of the limitations

period  pending confirmation  of  the plaintiff's  injury or  its

cause, but simply  stops the  clock until the  occurrence of  "an

event or  events .  . .  that were reasonably  likely to  put the

plaintiff on notice  that someone  may have  caused her  injury,"
                                      

Bowen, 408 Mass. at 207 (emphasis added).  Thus,  a plaintiff who
     

in the 1970s was told that her injury may have been caused by her

mother's ingestion of DES was unable to invoke the discovery rule

to save  the lawsuit she filed a decade later, when she felt more

certain of the causal connection.  See id. at 209-10.
                                          

     Applying  these principles  to the  case at  hand, Cambridge

Plating's  ability to invoke the  discovery rule --  and thus the

timeliness of its claims -- turns on when the company should have

known that Napco  might be  responsible for  the water  treatment

system's failing  performance.   In  Section  V, we  discuss  our

                               -18-

conclusion  that this question must  be answered by  the trier of

fact.    See  Riley, 409  Mass.  at  247-48  (jury should  decide
                   

disputed issues relating to statute of limitations).

                                V.

     To survive Napco's motion for summary judgment  based on the

statute  of limitations,  Cambridge Plating  must show  a genuine

issue of material fact as to whether it knew or should have known

of  its claims  before June  22, 1987.9   See  Fidler v.  Eastman
                                                                 

Kodak Co., 714  F.2d 192, 197-98  (1st Cir. 1983); Hoult,  792 F.
                                                        

Supp. at 145; Riley, 409 Mass. at 244, 247.  No one suggests that
                   

Cambridge  Plating  in  fact  knew the  source  of  the  system's

problems before  early 1989, and  the issue therefore  is whether

there is a factual  dispute over whether the company  should have

realized Napco's possible responsibility before that date.

     A  careful analysis of the  record persuades us  that such a

dispute  exists.  In finding that Cambridge Plating was on notice

of its claims in late 1985, the district court  relied heavily on

the company's having  learned at  that time that  the system  was

failing to  bring effluent discharges down  to acceptable levels.

The  court  felt  that   Cambridge  Plating's  knowledge  of  the

deficiencies meant that it knew that the performance warranty was

being breached.  Additionally,  consistent with its understanding

                    

     9  The lawsuit was filed on June  22, 1990.  As discussed in
Section III,  supra, certain of the claims have four-year, rather
                   
than three-year,  statutes of limitation, and  those claims would
be  timely even  if  Cambridge Plating  learned  of them  a  year
earlier, in  1986.  For the sake  of simplicity, because it makes
no  difference in  the result,  we discuss the  claims as  if all
needed to be filed within three years of their discovery. 

                               -19-

of the discovery rule, see Section IV supra, the court ruled that
                                           

Cambridge Plating was then on notice of the other claims as well.

     The system's inadequate performance  in late 1985 strikes us

as  far less portentous.  Beyond doubt, when the system first was

installed,  and throughout  Napco's debugging  process, Cambridge

Plating had no reason to suspect the serious flaws.   Omission of

the  static  mixer  was virtually  impossible  for  anyone but  a

wastewater treatment expert to  discover, both because the device

was  supposed to  be located  inside a  pipe and  because Napco's
                                    

diagrams  indicated that  it had been  installed.   Moreover, any

deficiencies presumably  were to be resolved  once Napco finished

its finetuning.

     When  the  problems persisted  despite  Napco's announcement

that debugging  was complete, two explanations theoretically were

available.  Either  the system  itself was defective,  or it  was

being  operated  improperly.   At  this point,  however,  the two

possibilities were not equally  weighted.  Cambridge Plating knew

that the  system was  technically complex and  required sensitive

operation.   And  Napco's  only response  to Cambridge  Plating's

inquiries was to suggest ways to improve operation.

     In these circumstances, we  do not believe Massachusetts law

requires  a finding that Cambridge  Plating was on  notice of the

system's defects.  A plaintiff is sufficiently aware of her cause

of  action,  and thus  should have  discovered  it, once  she has

received  "notice  of  likely cause,"  Fidler,  714  F.2d at  199
                                             

(quoted  in  Bowen, 408  Mass. at  207-08).   Accordingly,  as we
                  

                               -20-

understand the requisite notice,  the statute of limitations will

begin  to run once the plaintiff has enough information to target

the defendant  as a suspect,  though not necessarily  to identify

the  defendant as the culprit.   See Bowen,  408 Mass. at 207-08.
                                          

We think it within  a factfinder's province to conclude  that, in

late 1985,  Cambridge Plating had no basis for suspecting Napco's

workmanship  and  reasonably  attributed  the  system's  problems

solely to  its own deficient  operation.   If so, the  statute of

limitations would not yet have begun to run.10

     Cambridge  Plating  hired new  operators,  but  the problems

persisted.    So, in  late 1986,  the  company engaged  its first

expert evaluation of  the system.   This, too,  resulted in  only

operational suggestions.  Should  this expert have discovered the

defects?   Again, we believe this is a question properly answered

by the trier  of fact.   The record  contains little  information

about  the  first expert,  describing  him only  as  an assistant

instructor  for  a wastewater  treatment  course  at a  community

college who "worked on waste treatment for Hewlett Packard."  See
                                                                 

Affidavit of Edward Marullo, at 2.   Was he competent to evaluate

the  system?  Would even a well qualified expert necessarily have

uncovered the problem based on what  he knew about the system  at

                    

     10  The facts here contrast  with those in  White v. Peabody
                                                                 
Construction Co.,  386 Mass. 121 (1982),  where plaintiffs sought
                
to  recover damages  resulting  from widespread  window and  roof
leaks  allegedly  caused  by  defendants'   improper  design  and
construction  of   a  housing   project.    The   court  rejected
application of  the discovery  rule there because  the plaintiffs
"reasonably should  have known that  widespread water leaks  in a
newly  constructed building  are almost  certainly the  result of
design or construction defects."  Id. at 130.
                                     

                               -21-

that point?  Was it reasonable to rely on the schematics provided

by Napco showing that a static mixer had been installed?  Perhaps

the  second expert discovered the defects  only because, in light

of the earlier  expert's reasonable work, a more exhaustive study

now appeared necessary.11

     Because   the   record   leaves  these   subsidiary   issues

unresolved,  factual  questions  remain as  to  whether Cambridge

Plating should  have known  even by  the end  of 1986  of Napco's

possible  responsibility  for  the  system's failings.    If  the

expert's failure  to discover the defects was  reasonable, a jury

could find that Cambridge Plating continued to deserve protection

from the discovery rule beyond that time.12

     Whether  the rule's  impact, assuming  it reached  this far,

continued  on  through the  time of  actual  discovery is  also a

matter  for jury deliberation.  Was it reasonable for the company

to  wait another two years before seeking additional advice?  Was

there a point in  time after Cambridge Plating had  complied with

all of the  first expert's suggestions, still  without any change

in the  system's performance, that the  company reasonably should

have realized that Napco's work may have been to blame?

                    

     11 An affidavit from the second expert, Peter Moleux, states
that, in his opinion, "the defects in the system  could have been
discovered  only by someone  with expertise  and training  in the
field  similar  to mine  and only  after  a lengthy  and thorough
inspection and analysis."  See App. at 179   33.  Moleux reported
                              
that he spent "many days" identifying the system's problems. 

     12  Of  course,  claims  subject  to  four-year  limitations
periods  would be timely even  if the discovery  rule only tolled
the running of the clock through the end of 1986.

                               -22-

     In  short,  many  questions   remain.    To  determine  when

Cambridge  Plating "reasonably  should have  discovered" that  it

might have  claims against Napco  requires a  review of  specific

circumstances  about which the  record presently contains sketchy

information.  Consequently, the district court's grant of summary

judgment must be set aside.13

     Reversed and remanded. No costs.
                                    

                    

     13  We  are unpersuaded  by Cambridge  Plating's alternative
theories  that  the  statutes   were  tolled  because  (1)  Napco
concealed  omission of  the  static mixer  and  (2) Napco  had  a
fiduciary duty to disclose the omission but failed to do so.  See
                                                                 
generally White v. Peabody Construction Co., Inc., 386 Mass. 121,
                                                 
133-34 (1982).

                               -23-
