By Kevin Giles kgiles@startribune.com

The percentage of leaking septic systems in Washington County exceeds the state average, and evidence of damage to groundwater has continues to emerge, commissioners were told recently.

Thousands of property owners have outdated septic systems — many out of compliance with laws that govern sewage disposal — and the county is moving closer to arranging low-interest loans to encourage replacements. An estimated 17,000 systems dot the county, most of them on private land.

Washington County is working "to identify failing systems, especially around troubled water bodies," said Stephanie Souter, a planner in the county's Public Health and Environment division. County research shows most of the water table having "high" or "very high" sensitivity to pollution from failing septic systems.

Concern over the magnitude of the problem emerged several months ago when an uptick in housing sales, which triggered inspections, showed failing septic systems. Many owners don't realize they have a problem until waste backups occur in their houses, the county has said, and leaks can continue for years undetected.

About 48,000 Washington County residents use septic systems. That's the equivalent of 3.7 million gallons of wastewater per day, superseding the 3.5 million gallons a day treated at the St. Croix River wastewater plant. Some property owners even have cesspools, which are tanks with no bottoms that drain into groundwater.

If the County Board chooses to approve the loan program, funding would come from the state Agricultural Best Management Practice program. Washington County would become a "local lender" to administer the program, with a proposed interest rate of 1.5 percent over five years. About $10 million would be available in loans, Souter said.

"This is a great program and a well-needed program," said Commissioner Fran Miron, who asked that owners of septic systems see quick action once they apply for a loan. "I want to make sure we can be timely with our administration."

The projected starting date for the program is spring 2014.

Commissioner Gary Kriesel said an aggressive information campaign would be needed because the county shouldn't assume owners of septic systems realize they have a problem or can afford the estimated $15,000 to pay for a replacement. Threats to groundwater, he said, are widespread, and a "global solution" is needed because it's a regional problem.

"The state's got to recognize this as a huge, huge issue," he said after Souter's presentation.

Kriesel said he favored exploring whether state clean water funding might be available to help cut expenses for property owners.

Souter said the overall pollution from failing septic systems is showing up in algae blooms in lakes, rivers and streams. Enlisting the help of watershed districts, contractors and local governments will be needed to help educate residents, she said.

About 12 percent of all septic systems statewide are considered deficient, but Washington County's rate could be higher because of their relative age, officials said.

Commissioner haven't yet voted on the loan proposal.

Kevin Giles • 651-925-5037