Limits on Septic Tanks May Curb Construction

In a move that could curb housing construction in the Santa Rosa Valley and other rural areas of Ventura County, state water-quality officials adopted new restrictions on septic tanks Monday.

Under the policy adopted by the California Regional Water Quality Board, developers who install septic tanks will, in most cases, have to conduct an extensive study showing that they will not contaminate ground water.

Septic tanks catch waste materials from household drains and toilets. Solids are trapped in the tanks while liquids are allowed to percolate through the earth and into ground water.

Homes now using septic tanks are not affected by the new policy, which was adopted after studies blamed septic tanks in part for the presence of nitrates and other pollutants in some ground water.

“It’s going to make it a lot tougher for projects with lots of between one and five acres to go on septic tanks,” said Bruce Smith, of the county planning division.

Lots larger than five acres are exempt from the study requirement, and county regulations already ban septic tanks on most lots smaller than one acre.

The Santa Rosa Valley northeast of Camarillo would be the area most affected, Smith said.

About 280 houses on one-acre lots have been proposed for the Caston Trust area, Smith said, and applications have been filed or are expected soon for another 110 houses in the valley.

Under the new policy, unrecorded projects cannot proceed until the water study is completed, said Nancy Settle, another planning division official.

“The criteria seem pretty tough,” Smith said. “Many of these areas may have to go on sewers.”

He said he could not estimate how much a sewer hookup would add to the cost of a house, but said that the sewage plants nearest to the Santa Rosa Valley are in Camarillo and Oxnard, so major trunk lines would have to be installed. Such a project would be “tremendously growth-inducing” and controversial, he said.

The study requirement does not affect individual lot owners who want to build a single house, Settle said.

In such cases, she said, septic tanks will be allowed on lots as small as 20,000 square feet--a little less than half an acre.

“What the board is trying to address is subdivisions,” Settle said.

The new interim policy will apply until the water quality board concludes work on a permanent policy, probably in about a year, said Anne Saffell, chief of the water board’s planning unit.

The policy adopted Monday is less restrictive than one proposed by the board’s staff in April.

That plan would have required a minimum of two acres for a septic tank and would have required developers who use septic tanks to install sewer lines in areas deemed likely to need a sewage treatment system eventually.

The policy adopted Monday strongly recommends that developers install sewer lines for eventual hookup but does not require them.