O.W.L. Foundation v. City of Rohnert Park

Section 10910 of the Water Code requires a public water system to prepare a water supply assessment (WSA) that analyzes whether water supplies are sufficient for certain proposed development projects. If the water supply for the proposed project includes groundwater, the statute requires the water supplier to analyze whether groundwater supplies will be sufficient to meet the projected demand associated with the project. (§ 10910, subd. (f)(5).)

At issue in this appeal is whether the groundwater sufficiency analysis contained in a WSA adopted by appellant City of Rohnert Park (City) satisfies the requirements of section 10910, subdivision (f). The trial court concluded the sufficiency analysis did not comply with the statute and consequently granted a writ of mandate requiring the City to set aside its resolution adopting the WSA.

Appellants contend the trial court erred by requiring that a water supplier assess water demands and projected pumping by all others taking water from the same groundwater basin. They urge that the statute contains no such requirement but instead allows water suppliers flexibility in determining how to measure groundwater sufficiency for a…