West Virginia · West Virginia Legislative Rule 64CSR9
The West Virginia Bureau for Public Health writes the rule and local health departments issue permits.
Minimum tank
One to three bedroom dwelling.
Design flow
Held two days for settling.
Cost index
Regional labour and permits.
Sets the design flow and the legal minimum.
Code sizes on bedrooms, not people.
Used to size the matching drainfield. Unsure? Sandy loam is the common default.
Steep terrain almost everywhere, thin soils over shale and sandstone, and narrow valley bottoms with alluvium. Slope, not percolation, is frequently the limiting factor.
Contour trenches following the slope, and shallow placement where soil depth is limited. Where nothing works, holding tanks and, in some circumstances, aerobic units with discharge.
| Dwelling | Design flow | Minimum tank | With disposal |
|---|---|---|---|
| 1 bedroom | 300 gpd | 1,000 gal | 1,250 gal |
| 2 bedrooms | 300 gpd | 1,000 gal | 1,250 gal |
| 3 bedrooms | 450 gpd | 1,000 gal | 1,250 gal |
| 4 bedrooms | 600 gpd | 1,250 gal | 1,500 gal |
| 5 bedrooms | 750 gpd | 1,500 gal | 1,750 gal |
West Virginia requires a percolation test and site evaluation by the local health department, and licenses installers. Slope limits and proximity to streams are enforced carefully given the terrain.
The state sets a floor. These West Virginia counties are where the largest septic populations sit, and where local requirements most often exceed it.
| County | What makes it different |
|---|---|
| Kanawha | Charleston area; valley and hillside sites |
| Berkeley | Eastern panhandle growth, limestone karst |
| Jefferson | Fastest-growing county, karst constraints |
| Monongalia | Morgantown, steep terrain |
| Putnam | Suburban growth in the Kanawha valley |
A three-bedroom home at 150 gallons per bedroom produces 450 gallons per day of design flow. On sandy loam that needs roughly 750 square feet of absorption area. On clay loam it rises to about 2,250 square feet, and on clay a conventional field is usually not permitted at all. Run your own soil class through the drainfield calculator.
No statewide mandated residential interval. Use the pump schedule calculator to work out the interval for your tank size and household.
Regional labour and permit costs in West Virginia run about 90% of the national baseline. Here is what typical installations land at for a three-bedroom home:
| System type | Typical installed cost in West Virginia | When it applies |
|---|---|---|
| Conventional gravity | $8,100 – $14,400 | Good soil, adequate depth to water |
| Chamber system | $8,900 – $16,600 | Alternative to gravel trenches |
| Mound system | $15,400 – $30,200 | Shallow water table or thin soil |
| Aerobic treatment | $13,000 – $25,900 | Clay soil or small lots |
| Tank pump-out (service) | $290 – $580 | Every 3–5 years |
Replacing an existing system costs more than these figures — old-system removal and re-permitting add to every line. The replacement cost calculator covers that case, and the cost estimator adjusts all of the above for your bedroom count and soil.
Verify before you build. The figures above are state minimums compiled for planning, drawn from West Virginia Legislative Rule 64CSR9, Sewage Treatment and Collection System Design Standards. County and health district rules routinely exceed them, code text changes, and only West Virginia DHHR — Environmental Health Services or your local health department can confirm what applies to your parcel.
Send your sizing numbers to installers who work under West Virginia rules every day.