Whatcom County will not allow sewer extensions into rural areas after the state Department of Ecology earlier this month approved the Lake Whatcom Water and Sewer District’s sewer plan with tweaks to it.

The district cannot allow sewer extensions that are within its service area but are outside of Urban Growth Areas, which are places where cities and the county designate future growth to fill in.

But for water district Manager Jim Neher, the decision means that developments already vested have just one option — septic tanks — which have come under fire because leaking ones may harm Lake Whatcom water quality.

“In an area where we’ve been trying to get rid of septic systems around the lake, now we’re saying, the county is going to allow development, and they’re going to allow septic systems,” Neher said.

In the district’s plan, officials noted three subdivisions within the district’s boundaries but outside of a UGA. It’s unclear if any have already received approval for sewer extensions.

Allowing sewer access to those developments would violate the state’s Growth Management Act and Whatcom County’s comprehensive plan, said Steve Hood, the Ecology Department environmental engineer who worked on conditionally approving the district’s sewer plan.

County Planning and Development Services Director David Stalheim said in an e-mail to County Council members that his staff is still trying to figure out how the ruling affects developments already proposed and approved for sewer. But in a recent interview, Stalheim said he couldn’t name any developments that already have such approval. Hood said those with approval might not be stopped.

“I don’t know that anybody has a tool to stop them connecting up if they already have their approvals,” Hood said.

Asked if there was concern over septic tanks, Hood said that the state views “properly functioning septic systems and properly functioning sewer systems” as both being able to adequately manage sewage disposal. The issue would be if a septic system fails, Hood said.

In that case, the Whatcom County Health Department would be able to grant an emergency status, which would allow for a sewer extension into the rural area, Hood said.

But Neher said that the county has already approved urban levels of density in the watershed, and doing this still affects the will of some to get rid of septic tanks within the watershed.

“It kind of proves our point that that we’re not the ones driving development. The county is with their zoning,” Neher said. “It’s just a matter of semantics as far as we’re concerned, but we’re going to do our best to comply.”