Drain field repair and replacement
When wastewater surfaces in the yard or drains stop keeping up, the drain field is often the reason. Get it diagnosed before you replace it.
Drain field repair restores the part of your septic system where the soil finishes treating wastewater. Thurston County homeowners call when effluent surfaces in the yard or drains back up even after pumping. Because a drain field is usually the most expensive part to replace, the first step is always a diagnosis.
What are the signs of a failing drain field?
- Soggy ground or standing water over the field
- Sewage odor in the yard, especially after heavy water use
- Grass that's unusually green over the lines
- Backups even after the tank was pumped
- An inspection report noting ponding
Why do drain fields fail around Olympia?
Wet winters raise groundwater, and a field that barely keeps up in summer can be overwhelmed in January. Soils vary widely across the county, from gravelly prairie ground to heavier soils that drain slowly. Beyond weather and soil, the usual causes are:
- Solids escaping a tank that wasn't pumped often enough, or has a broken baffle
- Driving or parking on the field, which compacts soil and crushes pipes
- Roots working into the lines
- More water than the system was designed for, such as an added bedroom or leaking fixtures
- Age: every drain field has a working life
Can a drain field be repaired instead of replaced?
Sometimes. If the cause was excess water or solids from an overdue tank, fixing that and resting the field can help. Damaged sections of pipe can sometimes be replaced. A saturated or clogged field in poor soil usually needs new lines or a different system type, such as pressure distribution or a mound.
What affects the cost of drain field work?
- Repair versus replacement. Fixing a line is far smaller than a new field.
- Soil and site. Poor soil or high groundwater can require a pressure or mound system.
- Design and permits. Replacements in Thurston County need a design and a county permit.
- Access and restoration. Tight lots, trees and landscaping add equipment time and cleanup.
Prices come from the company doing the work, and a phone quote is only an estimate until someone has seen the system.
Where we connect you with help
Common questions
Can a failing drain field recover?
Sometimes. If the cause was excess water or solids from an overdue tank, fixing that and resting the field can help. A saturated or clogged field in poor soil usually needs repair or replacement.
Do I need a permit to replace a drain field?
Yes. Drain field replacements in Thurston County require permits and a design. Your septic company or designer handles this.
Related services
More background: Thurston County septic guide.
Septic backing up or alarm going off?
Call now instead of sending a form. Backups are a same-day problem.