Drain field repair and replacement
A failing drain field is the most expensive septic problem. Get it diagnosed correctly, and know what the county will require.
The drain field (also called a leach field or absorption field) is where effluent from the tank soaks into the soil for final treatment. When it fails, wastewater surfaces in the yard or backs up into the house. In Deschutes County, a drain field replacement is a major repair that needs a county permit, and the replacement system may be quite different from the original.
What are the signs of a failing drain field?
- Soggy ground or standing water over the field
- Bright green, fast-growing grass over the lines
- Sewage odors in the yard
- Slow drains that don't improve after pumping
- Backups after heavy water use
Why do drain fields fail?
- Solids carried out of a tank that wasn't pumped
- Overloading from too much water at once
- Compaction from vehicles or construction
- Roots in the lines
- Age
Why are replacement systems different in Central Oregon?
Deschutes County's pumice-derived soils drain fast, which can move effluent toward groundwater before it's well treated. Pressure distribution systems are used on small lots and fast-draining soils to spread effluent evenly. Sand filters and ATTs add treatment before the drain field. In southern Deschutes County, major repairs require advanced nitrogen-reducing treatment, and in the La Pine sub-basin, the county requires the maximum nitrogen-reducing ATT available.
What does the permit process involve?
A drain field, sand filter or treatment unit repair is a major repair permit through Deschutes County. The county reviews the site and the proposed system. In the south county, DEQ, including a staff hydrologist, helps set the treatment level for each site. Your septic company or designer can handle the application.
What affects the cost?
- System type required. Gravity, pressure distribution, sand filter or ATT.
- Lot size and soil. Small lots and fast-draining or shallow soils limit options.
- Location. South county nitrogen-reduction requirements.
- Permits and design.
- Ongoing maintenance. ATTs and sand filters require an annual service contract.
Prices come from the septic company after they've seen the system. We don't quote prices ourselves, and a phone estimate is only a starting point.
Where we connect you with help
Common questions
Can a failing drain field be repaired, or does it need replacement?
Sometimes a field can be rested or partly repaired, but a fully failed field usually needs replacement. A septic company can assess it.
Will I need an ATT if my drain field fails in La Pine?
Likely. Southern Deschutes County requires advanced nitrogen-reducing systems for major repairs, and the La Pine sub-basin requires the maximum nitrogen-reducing ATT available.
Related services
More background: Deschutes County septic guide.
Septic backing up or alarm going off?
Call now instead of sending a form. Backups are a same-day problem.