Facing a state-imposed deadline, King County officials plan to turn up the heat in Vashon’s Marine Recovery Areas, waterfront neighborhoods where failing septic systems are thought to be fouling beaches and polluting Puget Sound.

For the past three years, the county has worked to get 262 homeowners in six separate MRAs on Vashon to inspect their septic systems and repair those that are failing — efforts required by a 2006 state law crafted as part of a long-range plan to improve Puget Sound’s health.

County officials have held six public meetings, gone door to door, sent out informational mailings and held septic maintenance workshops in an effort to encourage compliance.

So far, however, only 34 percent of those homes within the beach-front communities targeted by the county have had their systems inspected and, if needed, improved or replaced them, said Larry Fay, the community environmental health section manager for Public Health – Seattle & King County.

The county now has a little more than six months left to meet a July 2012 state-imposed deadline, he said.

“We feel we’ve spent a lot of time talking to folks about what needs to be done. … Over the next months, we’ll be talking about compliance,” Fay said.

The county plans to send out letters this week to those homeowners who have yet to comply with the state law, letting them know that they now face “very specified time frames to complete things,” Fay said. Those home-owners who don’t respond, he added, will get another letter that says they’ll soon face civil penalties.

“This is not going away,” Fay said.

The county established its biggest recovery area along the western shore of outer Quartermaster Harbor — from Shawnee to Magnolia Beach — and several smaller ones along the eastern shores of Vashon and Maury in 2008. Homeowners within those areas are expected to have their on-site sewage systems inspected by a professional and, if necessary, repaired or replaced; they’re also to begin a regimen of annual inspections.

The law was prompted in part by the need to clean up beaches now closed to both state and tribal shellfish harvests because of the extent of the pollution. The situation is serious on Vashon, according to Fay, where some homes are dumping raw sewage into Quartermaster Harbor.

But some Vashon real estate agents say homeowners have failed to step up to the county’s requirements because of the daunting costs of a new system and the difficult nature of installing one. Many of the waterfront homes on Vashon are small cabins built in the 1930s and 1940s; some are on tiny lots up against steep banks.

“The cost is prohibitive. And the county hasn’t come up with any plan to assist people,” said Linda Bianchi, a Windermere real estate agent whose sons have a small beach-front cabin on Vashon. “I think if they could, more people would step forward. … I think most people have good intentions.”

Beth de Groen, who owns the Windermere office on Vashon, concurred. “I think it’s mostly about money,” she said.

She just sold a waterfront parcel where the homeowners installed a new system in advance of putting their home on the market. The system cost them $35,000, she said. But the couple, de Groen added, also felt “it was the right thing to do.”

“They didn’t like the idea that there was effluent going into the water,” she said.

Len Wolff, an agent with John L. Scott, said the new law has put a damper on sales within the MRA. “It’s a cause to pause for buyers,” he said.

Fay said the county continues to try to find funding to help homeowners secure low-interest loans to repair their systems. But without more information about the extent of the problem, he said, he’s hard-pressed to write a compelling grant request.

“That’s why we’ve told people, ‘You need to do this work, so we have a better application,’” he said.

But Fay said he’s optimistic about the situation on Vashon. While only 70 properties, or 34 percent of the homes within the MRA, are fully in compliance, many homeowners have begun the process, Fay said. What’s more, he said, the tone’s begun to change; homeowners, he said, are more receptive to the county’s information and more aware of what it is they need to do.

“This last year, we’ve seen quite a shift. So I feel better about where we are. But we’re running out of time,” he said.

Some homeowners, Fay said, have been taking a wait-and-see approach, “waiting around to see what would happen and see what their neighbors would do.”

Now, he predicts, many will begin to act.

“I think we’ll see quite a bit of movement over the next six months,” he said.