The Santa Margarita Water District and San Bernardino County were sued by environmental groups over a groundwater-pumping project in the Mojave Desert.

Los Angeles-based Cadiz Inc. has proposed pumping 16 billion gallons of water per year from under 45,000 acres it owns in a desert area of San Bernardino County.

The project is estimated to cost between $225 million and $275 million and would supply water for about 400,000 persons through six water districts in California.

The Santa Margarita Water District in Mission Viejo was the lead agency on the environmental-impact report for the project. The water district also agreed to buy 10% of the proposed water output.

County officials in San Bernardino have until the end of October to review the report.

The lawsuit was filed by the Center for Biological Diversity, the Sierra Club’s San Gorgonio chapter, the National Parks Conservation Association and the San Bernardino Valley Audubon Society. The organizations contend that San Bernardino County should have headed the project review because the project is in its territory.

The plaintiffs are arguing the environmental-impact report should be voided and a new one done by the county.