Despite California's ongoing struggles with water shortages, state regulators have adopted mandatory conservation measures that are substantially weaker and save less water than they originally planned.

Adopted by the State Water Resources Control Board, the regulations usher in a new phase of mandatory conservation for California.

They set long-term targets for water use that aim to account for myriad regional differences from climate to livestock ownership.

Individual residents won't be regulated, only suppliers, who must meet their conservation targets or face fines or other penatlies The costs of complying through 2050 are now estimated at $4.7 billion, which is largely expected to be passed onto ratepayers, but water agencies and their customers will also save about $6.2 billion, in large part from buying less water, according to the agency's analysis.

Water board staff estimate that through 2040 the measures will save 1.7 million acre feet of water, enough to supply almost half the state's population for a year but still substantially less than an earlier version.

Water regulators revised the proposal to delay enforcement of the conservation targets by two years, until 2027, and extend the deadline for ramping down outdoor water use by five years, starting in 2035.

Environmental groups and lawmakers say the weakened rules reduce and delay the water conservation that the drought-plagued state needs.

Many local water providers applauded the changes, which they said will soften impacts to customers and communities, but they told state regulators that the targets will still be difficult to meet.

They warned that the costs could hit low, and fixed-income members of their communities especially hard, and urged water official to provide more technical assistance and funding.

Suppliers are expected to meet the targets through a combination of rebates encouraging thriftier landscapes and appliances; rate changes penalizing thirstier water users and other measures.

For CalMatters, I'm Rachel Becker.