Why sewer leaks end up in Seattle crawl spaces
Older houses across Seattle, Burien and South King County often have clay or cast-iron drain lines and side sewers. Tree roots, ground movement and age crack them or pull joints apart. When the break is under the house, every flush and shower drains onto the crawl space floor. When the side sewer is blocked further out, sewage can back up and leak from joints under the house. In Seattle, the side sewer belongs to the property owner, so the repair is usually yours to arrange. The Seattle Public Utilities side sewer backup page advises calling a plumber first and contacting SPU if the plumber suspects the public main.
Seattle’s long wet season also keeps many crawl spaces damp, so sewage dries slowly and odor builds. Our crawl space cleaning team handles groundwater and mold under houses. This page covers the cases where the water is sewage.
What crawl space sewage cleanup includes
- Inspection and documentation of how far the sewage spread, with photos and moisture readings
- Removal of sewage and solids from the soil surface and debris under the leak
- Insulation removal where sewage or contaminated moisture reached the fiberglass between the joists
- Vapor barrier removal, since the plastic sheeting holds sewage and can’t be cleaned in place
- Cleaning and disinfection of joists, beams, the underside of the subfloor and the soil surface
- Drying with dehumidifiers and air movers, then deodorizing
- A new vapor barrier and insulation once the space is dry
Sewage is Category 3 water. The IICRC S500 consensus body lists it, along with wastewater that backs up from beyond a trap, as grossly contaminated. See our black water cleanup page for what that means for removal.
What to do right now
- Stop using water in the house: no flushing, showers, laundry or dishwasher. Each gallon ends up under the floor.
- Don’t go into the crawl space without gloves, boots and eye protection. The CDC recommends rubber boots, goggles and gloves for sewage cleanup.
- Close floor vents in rooms above the smell and keep children and pets out of those rooms.
- Call a plumber to find and fix the break. Before any digging to clear or replace a line, SPU advises calling Puget Sound Energy at 1 (888) 225-5773 so a gas line isn’t hit.
- Take photos through the hatch if you can do it safely.
When to call
Call us as soon as you smell sewage under the house or a plumber finds a broken line. We can start removal as soon as the leak is stopped. We handle crawl space sewage cleanup in Seattle, Burien, Renton, Des Moines and across King and Pierce County. For backups inside the house, see sewage backup cleanup; for a toilet that overflowed upstairs, see toilet overflow cleanup.
Call (206) 203-6155 for crawl space sewage cleanup, 24/7.
