I concur and write separately to explain why I believe regulation of water quality is among the “official duties” of the Public Utilities Commission (PUC or commission). (Pub. Util. Code, § 1759.)1 Some of my reasons go beyond those described by the majority and relate more specifically to the commission’s authority to promulgate water quality standards stricter than those of the California Department of Health Services (DHS), an issue central to the jurisdictional dispute.
Plaintiffs in these actions maintain that the 1976 amendment to section 770—which eliminated the prohibition on the PUC applying its water quality standards to regulated utilities and provided instead that any such standards it may apply shall not be “inconsistent” with DHS standards—means that PUC water quality standards may not differ in any way from those promulgated by DHS, which would bar the commission from imposing standards higher than those of DHS. Plaintiffs’ construction of the amendment renders it meaningless. If, as plaintiffs argue, the amendment means the PUC cannot apply its own standards, but only those of DHS, the amendment would have no different effect than the language it replaced, and the Legislature would have performed an idle act. Given the context in which the Legislature acted, the only sensible interpretation is that “inconsistent” means less rigorous, so that the purpose of the amendment to section 770 is analogous to that of the federal Safe Drinking Water Act (42 U.S.C. § 300f et seq.) (federal SDWA), which prohibits the states from enacting water quality standards less stringent than those established by the federal government, but permits them to impose more stringent requirements. (42 U.S.C. § 300g.)
Because, as the majority says, the Legislature established only that DHS water quality standards are “the minimum standards for the PUC to use in performing its regulatory function” (maj. opn., ante, at p. 271, italics added), the commission is free to subject regulated water utilities to stricter standards than are imposed by DHS.
*284The title of the PUC investigation in this case2 reflects the commission’s concern that the DHS standards it now applies may not adequately protect the public; and the PUC made clear during the proceedings that it was considering the promulgation of higher standards. As the commission stated, “we do not intend to reduce MCLs [maximum contaminant levels], Action Levels or similar standards which are terms of art in the lexicon of [Safe Drinking Water Act] law and regulation. Drinking water standards, including established MCLs, are minimum water quality requirements and we cannot and shall not tamper with those requirements. We do not intend to duplicate the processes employed by DHS and [the federal Environmental Protection Agency] to develop those standards. We do intend to employ the knowledge of these agencies as we pursue this investigation. The evidence adduced in this proceeding may support the development of additional operating practices for regulated utilities. If so, we would expect that such new rules either will fill an identifiable void, if any there is, in the DHS regulatory scheme or will be practices stricter than those of DHS and/or they will be practices particularly suited to the regulation of investor-owned water utilities. In any event, before we can determine what actions, if any, might better promote safe drinking water service by regulated water utilities, we must have a clear understanding of the safety status of existing regulation. Therefore, we need to receive evidence on the questions posed in the Oil [Order Instituting Investigation].”3 (Cal.P.U.C. Interim Opinion Denying Motions Challenging Jurisdiction to Conduct Investigation 09-03-013 (June 10, 1999) Dec. No. 99-06-054 [1999 Cal.P.U.C. Lexis 312 at pp. 73-74], italics added. (Interim PUC Opinion).) As the majority has noted, in its final opinion on water *285quality the PUC ordered a subsequent investigation and/or rulemaking proceeding to consider, among other things, whether DHS’s “action levels,” which are neither mandatory nor enforceable, should be mandatory for regulated utilities. (Maj. opn. ante, at p. 271, fn. 9.) Such a PUC rule would impose water quality standards higher than those imposed by DHS.
The substance of the PUC proceedings demonstrates that the commission is discharging its responsibility under section 761 to inquire whether the “practices” of or “service[s]” provided by defendant regulated water utilities are “unsafe,” and, if so, to fix the problem by “prescribing] rules for the performance of any service or the furnishing of any commodity . . . supplied by any public utility.” In short, the PUC inquiry into the adequacy of DHS standards, and any higher standards it may impose, are or would be in the performance of its “official duties” (§ 1759) to protect the public health and safety.
Significantly, DHS, which actively participated in the commission proceedings, never suggested that the PUC’s expressed interest in whether it needed to exercise its authority to subject regulated water utilities to water quality standards higher than those of DHS would, if acted upon, offend the federal SDWA or the state Safe Drinking Water Act (Health & Saf. Code, § 116275 et seq.) (state SDWA), and the DHS expressed no other objection to PUC assertion of authority to impose water quality standards higher than its own. On the contrary, DHS explained why it might be appropriate for the PUC to subject the almost 200 water utilities it regulates to higher standards than does DHS. According to DHS, “ ‘the increase in population growth and demand for drinking water throughout the state has diminished the options utilities have to reserve and select high quality sources of drinking water. The impact of groundwater contamination from industrial and agricultural practices has been significant in some areas of the state. Public water systems are no longer able to forego the use of contaminated drinking water sources, including those associated with Superfund sites, since that water may be needed to meet increased demand.’ ” (Interim PUC Opinion, supra, 199 Cal.P.U.C. Lexis 312 at p. 76.) Moreover, as DHS specifically acknowledged, “[t]here are some contaminants that were known to exist in drinking water sources but were never regulated.” (Ibid., italics added.)
DHS’s conduct in the PUC proceeding demonstrates that it does not believe the state SDWA (or the memorandum of understanding DHS originally entered into with the PUC in 1987) would prevent the PUC from imposing water quality standards higher than its own, or that such standards, including those pertaining to contaminants for which there now are no enforceable DHS standards, would be “inconsistent” with DHS standards. As the primary agency charged with implementing the state SDWA, DHS’s *286view is entitled to judicial respect. The questions whether an administrative agency properly applies legislative standards and acts within authority conferred by the Legislature are, of course, ultimately decided by the courts (Quackenbush v. Mission Ins. Co. (1996) 46 Cal.App.4th 458, 466 [54 Cal.Rptr.2d 112]), but an administrative agency’s “interpretation of a statute it routinely enforces is entitled to great weight and will be accepted unless its application of legislative intent is clearly unauthorized or erroneous.” (American Federation of Labor v. Unemployment Ins. Appeals Bd. (1996) 13 Cal.4th 1017, 1027 [56 Cal.Rptr.2d 109, 920 P.2d 1314], citing Pacific Legal Foundation v. Unemployment Ins. Appeals Bd. (1981) 29 Cal.3d 101, 109 [172 Cal.Rptr. 194, 624 P.2d 244].)
Neither does PUC’s General Order 103 bar the PUC from imposing higher water quality standards in the future. While at present this order only requires compliance with federal and state water quality standards, the phrase “except as otherwise ordered by the Commission,” must be interpreted as reserving the right to impose the higher standards the commission is allowed to impose under section 770. In any event, as the PUC had the authority to adopt General Order 103, so too does it retain power to repeal or amend it so that it is consistent with the imposition of PUC water quality standards higher than those promulgated by DHS.
For the foregoing reasons, as well as those set forth by Justice Chin for the majority, I agree that the PUC has independent regulatory authority to promulgate water quality standards applicable to the water utilities it regulates and that such standards may be the same as or stricter (but not less strict) than those promulgated by DHS under the state SDWA. There may be circumstances in which a superior court award of damages for injuries sustained by the provision of water standards or other rules applied by the PUC might interfere with the PUC’s performance of its “official duties,” and therefore violate section 1759,4 but, as the majority has explained, they are not presented by this case.
Presiding Justice of the Court of Appeal, First Appellate District, Division Two, assigned by the Chief Justice pursuant to article VI, section 6 of the California Constitution.
All statutory references are to the Public Utilities Code unless otherwise indicated.
“Investigation on the Commission’s own motion into whether existing standards and policies of the Commission regarding drinking water quality adequately protect the public health and safety with respect to contaminants such as Volatile Organic Compounds, Perchlorate, MTBEs, and whether those standards and policies are being uniformly complied with by Commission regulated utilities.” (Cal.P.U.C. Order Instituting Investigation No. 98-03-013 (Mar. 12, 1998) [1998 Cal.P.U.C. Lexis 73].)
These statements appear to represent a substantial policy change for the PUC, as the commission has heretofore consistently and rather summarily rebuffed consumer complaints that the DHS standards it applies are inadequate. For example when, in 1966, the PUC was asked to order “optimum” fluoridation of drinking water, the commission held: “With respect to the purity and safety of drinking water, the Commission will not question the findings and recommendations of the California Department of Health, which is charged with such responsibility.” (City of San Jose v. San Jose Water District (1966) 66 Cal.P.U.C. 694, 698.) Similarly, in 1972, the PUC again rejected complaints concerning the quality of a purveyor’s water: “The State Board of Public Health [DHS] has the authority ... to suspend or revoke a utility’s water permit at any time if it determines that the water is or may become unpure or unwholesome. Under [the Health and Safety Code],- and in accordance with General Order 103, it is not appropriate for the Commission to determine this question. Petitioners should direct their allegations on this question to the [DHS].” (Washington Water & Light Co. (1972) 73 Cal.P.U.C. 284, 303; see also Pool v. Mokelumne River Power & Water Co. (1918) 15 C.R.C. 38, 39 [“[t]he question of the healthful quality of the water is one to be passed on by the State Board of Health.”].)
For example, under section 735 the PUC has authority to receive and rule on claims for damages resulting from the violation of any of the provisions of sections 494 (relating to common carrier rates and fares) or 532 (relating to the rates, tolls, rentals and other charges imposed by public utilities), even though a suit seeking such damages could alternatively be instituted “in any court of competent jurisdiction.” Section 1759 would clearly bar a superior court from entertaining a claim for damages for violation of section 494 or 532 that had previously been submitted to and rejected by the commission.