Conditions at a Lake County subdivision suffering a landslide last month worsened Sunday when several red-tagged homes sustained additional damage.

Five homes had been red-tagged in the Lakeside Heights subdivision over the past several weeks, with several of the homes pulling off of their foundations. One home has been steadily sinking into the ground, and another is now scheduled for demolition.

"Summary abatement for one of the homes was approved Monday," said Lake County Supervisor Anthony Farrington. Farrington's district includes Lakeside Heights.

The Lake County Board of Supervisors unanimously declared a local emergency April 16. The board issued a proclamation asking Gov. Jerry Brown to declare a state of local emergency and also request a similar declaration from President Obama.

"The proclamation was issued so we could tap into both state and federal funding for this subdivision," said Farrington.

A leak in a homeowner's association irrigation line was determined to have caused water saturation leading to the hill's instability, according to a report released by Lake County Special Districts on April 4. The line was shut off to prevent further damage.

"There's two separate slides that are going on," said Kevin Ingram, an official with Special Districts. "In one area, the houses are buckling in and coming down on themselves."

Special Districts first discovered the issue when hillside movement caused damage to a public sewer line within the subdivision March 21. An emergency bypass was installed to pump sewage from the neighborhood, but a permanent repair cannot be completed until the landslide is stopped.

The county allocated $50,000 to hire a leak detection firm and a geotechnical firm to conduct testing of the area, and a potential source of water saturation was traced to a leak in a homeowner's association irrigation line.

Farrington said he believed the landslide stemmed from a cumulative effect of water saturation, unstable soil, and foundational problems.

"It definitely raises questions in terms of how some of the homes were built," said Farrington.

Over 25 homes remain in danger within the subdivision, and the neighborhood's water, sewage and storm drain systems are also threatened, said county deputy administrator Janet Coppinger.

The county's Public Works Department put barricades up on nearby Hill Road, to prevent landslide conditions from affecting primary access to Sutter Lakeside Hospital, said Farrington.

Several other roads are at risk of being shut down if the landslide worsens, including Lancaster Road and Downing Road, said Farrington.

Santa Rosa geotechnical firm RGH Consultants will present a report to the board Tuesday, outlining a recommendation to relocate existing county water and sewer infrastructure, said Ingram.

"Right now it's really about how do we preserve the integrity of our water and sewer infrastructure — we've also requested state assistance," said Farrington. "We need to protect these folks and prevent further sliding."

Staff Writer Melody Karpinski can be reached at 521-5205 or Melody.Karpinski@pressdemocrat.com