Addressing the Economic Burden of Aging OSS in the Puget Sound Region

Aerial view of West Seattle and Puget Sound. Photo Alex Rosas via Unsplash

New research in Coastal Management by Sabine Postma and colleagues examines who bears the cost of Puget Sound's failing septic systems, and how communities can pay to fix them

Hundreds of thousands of septic systems across Puget Sound are aging past their limits. When one fails, the cost of fixing it falls almost entirely on a single household. A working septic system protects far more than the property it sits on. On-site sewage systems (OSS) keep untreated waste out of the groundwater, the shellfish beds, the drinking water, and the beaches that define the region.

That is what makes this an economic problem as much as an environmental one. Cost is the biggest barrier, and it lands hardest on the low-income urban neighborhoods least able to absorb it, historically excluded from government-funded sewer infrastructure. The disparities are stark. Homeowner expenses range from about $4,000 for basic OSS maintenance to $124,000 for a sewer connection, depending on location and what infrastructure is already available. The failures don't stay on the property, but the bill does.

"It is one thing to know the number of septic systems in the region," said lead author Sabine Postma, Senior Research Associate at Greene Economics, "but the problem becomes much more apparent when you add a rough price tag to it."

The numbers are large. In King County alone, addressing systems more than 20 years old could cost homeowners an estimated $3.7 billion, and nearly $3 billion of that is already overdue, for systems past their 30-year lifespan. In 2011, failing systems downgraded 4,000 acres of Samish Bay shellfish beds.. No single fix closes a gap that size. The research points instead to a portfolio of financing options, including green bonds, community lending such as Craft3's Clean Water Loans, and models from as far afield as Chile's rural health services, each matched to a community's situation.

"Most folks don't realize the scale of this issue, or that it is an issue at all," Postma said. Without public pressure, she warns, decision-makers will keep reaching for duct tape rather than investing in long-term solutions.

There are early signs of movement. King County's Equitable Wastewater Futures Program, which draws on the cost estimates in the research, has deployed $2 million to extend sewer connections to qualifying homes, a preview of what becomes possible once decision-makers can see the full economic picture.

The full study, From Wicked Problem to Innovative Solutions: Addressing the Economic Burden of Aging OSS in the Puget Sound Region, is available in Coastal Management.

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