In Brydon v. East Bay Mun. Utility Dist. (1994) 24 Cal.App.4th 178, a municipal water district imposed a variable rate structure for which the price increased with consumption. This price "structure of the District was a response to state mandated water resource conservation requirements." (Id. at p. 192.) Even though a rate varied among customers, the Brydon court rejected a challenge to the increased payment for greater consumption as a tax for which voter approval was necessary. Brydon holds the voter approval requirement "does not apply to every regulatory fee simply because, as applied to one or another of the payor class, the fee is disproportionate to the service rendered." (Id. at p. 194.)