OPINION
LOPEZ, Judge.This appeal grows out of a suit by water users in the Adobe Acres Subdivision in Albuquerque against the utility which supplied their water, Valley Utilities, Inc.
The action was brought by five individual plaintiffs and the Adobe Acres Improvement Association on behalf of themselves and 475 water users in the subdivision. The plaintiffs asked tort and contract damages by reason of the utility’s failure to supply water meeting certain minimum standards of quality. Following a jury verdict for the plaintiffs, the defendant has appealed raising numerous issues of law.
I. Class Action
The defendant’s first point of error is that the case should never have been permitted to proceed as a class action. The defendant asks that the judgment be affirmed only with respect to the individual named plaintiffs. The defendant raises a number of arguments with respect to this point, but rather than specifically enumerating all of them we shall refer to them in the course of the opinion.
The Adobe Acres Subdivision contained 475 homes which subscribed to the defendant’s service. Of these homes 272 households belonged to the Adobe Acres Improvement Association. This Association is a nonprofit corporation. Prior to the start of the trial, the plaintiffs attempted in two different ways to inform residents of the subdivision of the pendency of the suit. One way was the distribution of a one page notice which was addressed to “Resident of Adobe Acres” and which stated that a suit had been filed against Valley Utilities, Inc. It warned that all residents would be bound by the judgment unless they notified the court or the plaintiffs’ attorneys that they wished to be excluded. This notice was delivered by eleven adult residents of the subdivision; the distribution committee chairman testified the method of delivery was to give the notice to the resident personally, or if the resident was not home, to put it in the screen door or the mailbox. Secondly, the Association published a newsletter which was also distributed to all residents of the subdivision; the method of distribution is unclear from the record. The newsletter did not inform the residents that the suit was binding, or that they could intervene.
The defendant objected throughout the proceedings to allowing the case to proceed as a class action. Nonetheless, the case was presented as a class action and the jury was so instructed. The jury verdict was for 475 members of the class in the amount of $1,000.00 apiece. The trial judge entered judgment for the 272 persons who were members of the Association, deeming them members of a “true” class. He directed that notice be given to the other residents of the subdivision and that they be permitted to intervene upon application. These nonmember residents were said to constitute a spurious class.
A major source of confusion in the case has been created by the distinctions between “old” Rule 23 and “new” Rule 23 of the Rules of Civil Procedure. Section 21-1-1(23), N.M.S.A.1953 (Repl. Vol. 4), and Rule 23, Fed. Rules of Civ.P., respectively.
New Mexico’s Rule 23 reads as follows:
"Rule 23. Class actions.
“(a) Representation. If persons constituting a class are so numerous as to make it impracticable to bring them all before the court, such of them, one [1] or more, as will fairly insure the adequate representation of all may, on behalf of all, sue or be sued, when the character of the right sought to be enforced for or against the class is
“(1) joint, or common, or secondary in the sense that the owner of a primary right refuses to enforce that right and a member of the class thereby becomes entitled to enforce it;
“(2) several, and the object of the action is the adjudication of claims which do or may affect specific property involved in the action; or
“(3) several, and there is a common question of law or fact affecting the several rights and a common relief is sought.”
New Mexico has not adopted the amendment to this rule which was implemented in the federal system in 1966.
Under our Rule 23 the crucial question is the species of class. This determination requires an examination “of the abstract nature of the rights involved”. Committee Note of 1966 accompanying amendment to Rule 23, Fed. Rules of Civ. P.
Once the classification is determined, the question of whether the judgment is binding on absent parties is resolved. This process of categorization has been assailed as irrelevant to the criteria which should determine whether absent parties are bound (Developments in the Law-Multiparty Litigation in, the Federal Courts, 71 Harv.L. Rev. 874, at 936 (1958)) and it is such criticism which led to the substantial amendment of this rule. Nonetheless, we shall accord the traditional interpretation to our rule, since it has not been amended.
The threshold question is whether the subdivision members form a true or spurious class. Rule 23 directs attention to the nature of the rights which the class seeks to enforce. In order to form a true class, the rights must be “joint” or “common” to the class. In order to form a spurious class, the rights must be “several” and there must be common questions of law and fact. “Joint” has a well accepted meaning in the law,, and has not proved difficult to apply. Moore, in his Treatise, says a right is joint if, in the absence of the class action device, joinder would be essential. 3B Moore’s Federal Practice jj 2308 (2d Ed. 1975); Tunstall v. Brotherhood of Locomotive Firemen and Enginemen, 148 F.2d 403 (4th Cir. 1945). The right involved here is not joint. The concept of a “common” right has caused more difficulties. See, Chafee, Some Problems of Equity, 255-57 (1950); 7 Wright and Miller, Federal Practice and Procedure: Civil, § 1752 at 516 (1972). It acquires meaning when contrasted to the rights asserted by a spurious class.
In this case a persuasive argument can be made that all plaintiffs have been injured by the same breach of duty by the defendant and in this sense claim a common right. However, the plaintiffs are asserting that the defendant owes them duties as individuals. In addition, the residents might have been damaged in varying degrees, and since our true class action does not provide for “opting out” of a class, all class members would be bound by the common judgment and unable to receive their individual damages. We conclude that the subdivision residents do not form a true class since they are not enforcing a right held in common. They do form a spurious class, in that common questions of law and fact relating to the defendant’s actions are raised by their claims.
Decisional law, although admittedly far from consistent, lends support to our conclusion. In Rank v. (Krug) United States, 142 F.Supp. 1 (S.D.Cal.1956), various landowners were permitted to sue as a true class when they sought injunctive relief against the government’s interference with riparian rights. The court noted that the right sought to be enforced was a common one to water from a common source, and distinguished it from the situation where the parties were seeking an adjudication of their individual rights to water. This case was later discussed in Puget Sound Alumni of Kappa Sigma v. City of Seattle, 70 Wash.2d 222, 422 P.2d 799 (1967). In Puget Sound a group of abutting landowners sued to recover amounts wrongfully collected by the city upon their petition to vacate certain streets. The amounts paid by the landowners varied with the appraised values of the vacated streets, yet the legal issue was identical for each landowner. The court held the claims were several, and the class was therefore spurious. Compare cases discussed in Wright and Miller, supra, at 516-17 with those discussed at 528-34.
The plaintiffs do not contend that the nonmembers of the Association are members of a true class. They do maintain, however, that the Association constitutes a true class and that the judgment is therefore binding on the Association members. Their first argument is based on the common predicament and jural relationship existing between members of the Association. Since the predicament was common to all subdivision residents, it is the jural relationship upon which this argument rests. The Association is incorporated as a nonprofit corporation, and nonprofit corporations have the right to sue. Section 51-14-30, N.M.S.A.1953 (Repl.Vol. 8, pt. 1). However, a corporation’s right to sue for relief as an entity and its right to sue for recovery for its individual members is not identical. This distinction is explained in Gonzales v. Oil, Chemical and Atomic Workers International Union AFL-CIO, 77 N.M. 61, 419 P.2d 257 (1966) in the analogous situation of a suit against an unincorporated association. In Gonzales a union was sued for damages incurred during a labor dispute. The court held that the union, as an entity, could be sued under the New Mexico statute which provides that an unincorporated association may be sued in its own name. Section 51-18-5.1, N.M.S.A.1953 (Repl. Vol. 8, pt. 1). However, the court also held that individual union members could not be held individually liable under this statute without proof of a Rule 23 class. Thus, the jural relationship is unavailing, except insofar as individuals have rights as members of that entity, which is a claim not at issue here. Compare Montgomery Ward & Co. v. Langer, 168 F.2d 182 (8th Cir. 1948) with Farmers Co-operative Oil Co. v. Socony-Vacuum Oil Co., 133 F.2d 101 (8th Cir. 1942).
The plaintiffs also argue that cases arising under New Mexico’s other class action statute, § 21-6-1, N.M.S.A.1953 (Repl.Vol. 4), should be considered as guidance for the nature of a true class action. This statute is based on Rule 38 of the Equity Rules of 1912, which in turn formed the basis of our present Rule 23. 3B Moore’s Federal Practice ¶23.02[1] at 23-74 (1975). What can be gained by reference to this rule is unclear. The binding effect of judgments on absent parties under Rule 38 was unsettled. 7 Wright and Miller, Federal Practice and Procedure: Civil § 1751 at 509 (1972). In all of the cases relied on by the plaintiffs, the relief sought was injunctive or declaratory, (see, e. g., Pecos Valley Artesian Conservancy District v. Peters, 50 N.M. 165, 173 P.2d 490 (1945); Key v. George E. Breece Lumber Co., 45 N.M. 397, 115 P.2d 622 (1941)) so that the commonality of the relief sought is apparent.
Finally, we are faced with the problem of determining what rights under the judgment are possessed by this class which we here hold to be spurious. The case was tried and presented to the jury, as a class action involving a class of 475 resident water users. The jury verdict was for 475 persons in the amount of $1,000.00 apiece. Following the verdict the court entered judgment for the members of the Association and deferred judgment for the other residents until they returned the applications for intervention. We approve the procedure devised by the trial judge for the nonmember residents and remand with directions to allow intervention by the Association members under the same procedure.
In endorsing the intervention procedure, we are guided by the authority of Union Carbide and Carbon Corporation v. Nisley, 300 F.2d 561 (10th Cir. 1962). In that case the Tenth Circuit approved this approach because it results in “ . more expeditious and efficient disposition of litigation.” Although no New Mexico ca^es have dealt with the issue of intervention in the context of a class action, the principles established in other intervention cases are helpful. The timeliness of intervention depends upon the circumstances of each case. Apodaca v. Town of Tome Land Grant, 86 N.M. 132, 520 P.2d 552 (1974). The trial judge is given a great deal of discretion in determining whether to allow intervention. Apodaca v. Town of Tome Land Grant, supra; Cooper v. Albuquerque City Commission, 85 N.M. 786, 518 P.2d 275 (1974); Tom Fields, Ltd. v. Tigner, 61 N.M. 382, 301 P.2d 322 (1956). Most importantly, the decision whether to allow intervention is governed by equitable principles. Richins v. Mayfield, 85 N.M. 578, 514 P.2d 854 (1973). In the case before us the action was tried as a class action. The jury verdict was for the whole class and the judge included the whole class in his judgment. The defendant is therefore not prejudiced by allowing the absent parties to be identified, since the jury has already determined that defendant is liable and the defendant has not challenged the damage award. Finally, we do not understand why the defendant would want the result otherwise. If we were to deny the absent members’ right to intervene, the defendant would be faced with separate suits by each of them, with the result foreordained. The court’s statement in Union Carbide is apt here: “Defendants’ liability and the extent thereof has been completely proven by the named plaintiffs and it would be grossly redundant to say that it must be proven again by the unnamed members of the represented class.” Union Carbide and Carbon Corporation v. Nisley, supra.
II. Primary Jurisdiction
The second point raised by the defendant is that the doctrine of primary jurisdiction applied to this case and the trial court was without jurisdiction to decide it.
Primary jurisdiction, as interpreted by the New .Mexico Supreme Court in Norvell v. Arizona Public Service Co., 85 N.M. 165, 510 P.2d 98, 60 A.L.R.3d 653 (1973), is essentially a doctrine of comity between the courts and administrative agencies. The invocation of the doctrine depends on whether the questions presented are “exclusively factual issues within the peculiar expertise of the commission” or “if statutory interpretation or issues of law are significant”. Wisconsin Collectors Assn. v. Thorp Finance Corp., 32 Wis.2d 36, 145 N.W.2d 33 (1966).
In the case before us the trial court was correct in assuming jurisdiction. The contrast with the situation in Norvell is pronounced. In Norvell, the plaintiffs were asking a court to declare in the context of a public nuisance action, that the defendants’ actions were harmful. This .would have required the court to formulate a standard of harmfulness, which would presumably be determined independently of the standard already established by the Board. In our case the standard had been set by the Public Service Commission and the Environmental Improvement Agency and the plaintiffs asked a jury to answer the traditional legal question of whether the duty established by that standard was breached.
In Norvell, the court considered at great length the powers and duties entrusted to the agency, in determining whether the agency had jurisdiction over the plaintiffs’ complaints. The relief asked was identical to the relief which the agency could have granted. The plaintiffs here had originally asked injunctive relief, but at the court’s order amended their complaint to ask only monetary relief. The Environmental Improvement Agency and Public Service Commission have no expertise in considering tort and contractual claims and are without power to grant the relief that the plaintiffs have asked.
The Environmental Improvement Agency, which has filed an amicus brief asking that the doctrine of primary jurisdiction be held not to apply, has stated that they are without jurisdiction to act on the plaintiffs’ complaint. They point to § 75-39-12 of the Water Quality Act (§§ 75-39-1 through 75-39-12, N.M.S.A.1953 (Repl. Vol. 11, pt. 2)) which evidences the legislative intent that common law remedies against water pollution are preserved. Specific legislative declarations that common law remedies are unimpaired are uniformly respected when primary jurisdiction questions arise in the field of public nuisance. 60 A.L.R.3d § 2[a] at 669 (1974). See, People v. Los Angeles, 160 Cal.App.2d 494, 325 P.2d 639 (D.Ct.App.2d D.1958); J. D. Jewell, Inc. v. Hancock, 226 Ga. 480, 175 S.E.2d 847 (1970); State v. Town of Huntington, 67 Misc.2d 875, 325 N.Y.S.2d 674; aff’d 37 A.D.2d 858, 326 N.Y.S.2d 981 (S.Ct.1971).
The trial court correctly retained jurisdiction of the case.
III. Modification of Instruction
The defendant argues that the trial court’s modification of a uniform jury instruction constitutes reversible error. The instruction given was
“No. 31—In fixing the amount of money which will reasonably and fairly compensate the plaintiffs, you are to consider that a person who is damaged must exercise ordinary care to minimize existing damages and to prevent further damages. Plaintiffs may not recover for losses which could have been prevented by reasonable efforts on his part, but the cost of minimizing damages may be considered a compensable damage.” U.J.I. 14.27, with the addition of underlined segment which was added by the trial court.
The discussion of the instructions took place off the record. The trial court did not state of record reasons for the modification as is required by statute. Section 21-1-1(51) (1) (c), N.M.S.A.1953 (Repl. Vol. 4); Anderson v. Welsh, 86 N.M. 767, 527 P.2d 1079 (Ct.App.1974). Nonetheless, there was evidence in the record tO' support the modification and the defendant has failed to show any prejudice resulting from the modification. Jewell v. Seidenberg, 82 N.M. 120, 477 P.2d 296 (1970).
IV. Addition of an Instruction
The defendant objects because an instruction was given regarding a corporation’s liability for actions committed while the corporation was under different ownership. This instruction is not found in U.J.I. The defendant does not argue that the instruction given does not meet the requirements of § 21-1-1(51) (1) (e), N.M. S.A.1953 (Repl. Vol. 4), but rather that the Committee Comment to U.J.I. 4.11 states that U.J.I. 4.11 is sufficient for any issue of liability of a corporation. The Committee Comments are not the equivalents of the Directions for Use. Thus, in this very instruction the Directions for Use suggests an additional instruction may be necessary, despite the contrary suggestion in the Comment. No error was committed in giving an additional instruction.
V.Cross-examination
The defendant’s fifth point of error is that the trial court erred in limiting its cross-examination of Mr. Wright, the state’s Water Quality Control Director. The defendant contends that Mr. Wright on direct examination had recommended installation of water softeners on a system wide basis, instead of in individual homes and that the defendant should therefore have been allowed to show that no other communities had been required by Mr. Wright to have such a system. To the degree the questioning would have related to the Environmental Improvement Agency’s enforcement policies it was irrelevant, because the issue was the reasonableness of the actions taken by this defendant and this reasonableness varied with the circumstances of every system. The refused questioning was helpful in demonstrating the weaknesses of one of the suggestions made by the witness. However, we fail to see any prejudice to the defendant since the proffered question had already been asked on direct examination. The witness testified that one community did have a softening procedure but the cost and management of that system had been unsuccessful. He added that he knew of no other systems which softened water on a system wide basis. The refused question was answered and therefore no prejudice occurred.
VI.Set-off Damages
The defendant complains of the refusal of the trial court to allow him to present evidence of set-off damages. These damages were offered with respect to certain named plaintiffs who maintained their own wells and who had asked special damages. Since the jury awarded no special damages, and since the defendant had only asked for damages as a set-off against special damages awarded these plaintiffs, the question is moot.
VII. Defendant’s Financial Condition
The defendant appeals the trial court’s refusal to allow him to present evidence of the utility’s financial condition. The purpose of introducing this evidence, we are informed on appeal, was to demonstrate that the expenses incurred in making these improvements would have resulted in high costs to consumers. This argument is irrelevant in a case based on liability in tort and breach of contract. Furthermore, the rate relief which the Public Service Commission might have given had the defendant pursued ameliorative measures is entirely distinct from the relief sought in this case. See, Southwestern Public Service Co. v. Artesia Alfalfa Grower’s Association, 67 N.M. 108, 353 P.2d 62 (1960).
VIII. Res Judicata
The defendant argues that the rulings of the Public Service Commission are res judicata with respect to the members of the Adobe Acres Improvement Association. This contention was not pled in the answer and is therefore waived. Section 21-1-1(8) (c), N.M.S.A.1953 (Repl. Vol. 4, Supp.1973 (addendum)); Skidmore v. Eby, 57 N.M. 669, 262 P.2d 370 (1953).
The case is affirmed with respect to liability. With respect to damages the case is remanded to allow the Association members to intervene on terms consistent with this opinion.
IT IS SO ORDERED.
HERNANDEZ, J., concurs.