Septic pumping in Lewis County, Idaho costs $300-$550 (avg $400). A new septic system installation costs $5,800-$11,550. Approximately 497 homes in this county use septic systems.
Septic System Costs in Lewis County
| Service | Low | Average | High |
|---|---|---|---|
| Pumping / Cleaning | $300 | $400 | $550 |
| Routine Inspection | $200 | $300 | $400 |
| Real Estate Inspection | $400 | $550 | $750 |
| Minor Repair | $750 | $1,050 | $5,050 |
| Conventional Installation | $5,800 | $8,250 | $11,550 |
| Aerobic System Installation | $10,800 | $15,450 | $21,650 |
| Drainfield Replacement | $5,800 | $8,250 | $11,550 |
| Perc Test | $900 | $1,250 | $1,750 |
Cost estimates based on regional market data for Lewis County, Idaho. Actual costs depend on system type, site conditions, and provider.
Groundwater & Water Table in Lewis County
Monitoring Wells
1
Avg Depth to Water
202 ft
Median Depth
202 ft
Shallowest Recorded
202 ft
Water table depths in this county are generally favorable for conventional septic systems.
Source: USGS National Water Information System. Based on 1 measurements from monitoring wells.
Septic Regulations & Permits in Lewis County
State Regulatory Body
Idaho Department of Health/Environment
Inspection Required for Home Sale
No / Varies
Nitrogen Reduction Areas
No
Advanced Treatment Required
No
Contact county health department for specific requirements.
Contact the Lewis County health department for current permit requirements, fees, and approved system types.
Septic System FAQ for Lewis County
How much does septic pumping cost in Lewis County?
Septic pumping in Lewis County, Idaho typically costs between $300 and $550, with an average of $400. Costs vary by tank size (1,000-1,500 gallons is typical), ease of access, distance from the pumping company, and how full the tank is. Most homeowners should pump their tank every 3-5 years.
How much does a new septic system cost in Lewis County?
A conventional septic system installation in Lewis County typically costs $5,800-$11,550. An aerobic treatment unit (ATU) costs $10,800-$21,650. Costs include the tank, drainfield, permits, and labor.
Do I need a permit for a septic system in Lewis County?
Yes. Virtually all counties in Idaho require a permit before installing, repairing, or replacing a septic system. The permit process typically involves a soil evaluation or percolation test, system design by a licensed professional, application to the county health department, and one or more inspections during installation. Contact the Lewis County health department for current requirements and fees.
What soil types are in Lewis County and how do they affect septic systems?
Contact the county health department for soil evaluation requirements.
How often should I pump my septic tank in Lewis County?
The EPA recommends pumping your septic tank every 3-5 years for a typical household. The exact frequency depends on tank size, household size, and water usage. A 1,000-gallon tank serving a family of 4 should generally be pumped every 3 years. Some counties in Idaho have mandatory pumping schedules — check with your local health department.
How long does a septic system last in Lewis County?
A well-maintained septic system in Lewis County typically lasts 25-30 years, though some components may need attention sooner. The concrete septic tank itself can last 40+ years, while the drainfield — the most critical and expensive component — usually lasts 15-25 years depending on soil conditions. Regular pumping every 3-5 years and avoiding excess water usage are the two most effective ways to extend system life.
Data last updated: 2026-04-13