Septic Systems in Knox County, TN

Regulations, costs, soil data & local providers

Pop. 478,971 ~15% on septic ~28,738 septic homes Well drained soil

Septic pumping in Knox County, Tennessee costs $300-$550 (avg $400). A new septic system installation costs $5,600-$11,200. USDA soil data rates 0% of county soils as suitable for septic absorption fields. Approximately 28,738 homes in this county use septic systems.

Septic System Costs in Knox County

ServiceLowAverageHigh
Pumping / Cleaning$300$400$550
Routine Inspection$200$300$400
Real Estate Inspection$400$550$750
Minor Repair$700$1,000$4,900
Conventional Installation$5,600$8,000$11,200
Aerobic System Installation$10,500$15,000$21,000
Drainfield Replacement$5,600$8,000$11,200
Perc Test$850$1,200$1,700

Cost estimates based on regional market data for Knox County, Tennessee. Actual costs depend on system type, site conditions, and provider.

Soil & Septic Suitability in Knox County

Drainage Class
Well drained
Hydrologic Group
B
Unique Soil Types
34
Avg Bedrock Depth
1.8 ft

Dominant Soil Types

Soil SeriesCoverageDrainageHydro Group
Minor components 831 - -
Dewey 604 Well drained B
Corryton 576 Well drained C
Fullerton 457 Well drained B
Collegedale 440 Well drained C

Septic Tank Absorption Field Suitability

USDA NRCS rates soil suitability for septic absorption fields across this county:

Not Limited (Good)0%
Somewhat Limited25.5%
Very Limited74.5%

Overall rating: Very limited

Source: USDA NRCS Soil Survey Geographic Database (SSURGO)

Septic Regulations & Permits in Knox County

State Regulatory Body
Tennessee 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 Knox County health department for current permit requirements, fees, and approved system types.

Septic System FAQ for Knox County

How much does septic pumping cost in Knox County?
Septic pumping in Knox County, Tennessee 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 Knox County?
A conventional septic system installation in Knox County typically costs $5,600-$11,200. An aerobic treatment unit (ATU) costs $10,500-$21,000. Given the predominantly well drained soils in this area, some sites may require alternative system types. Costs include the tank, drainfield, permits, and labor.
Do I need a permit for a septic system in Knox County?
Yes. Virtually all counties in Tennessee 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 Knox County health department for current requirements and fees.
What soil types are in Knox County and how do they affect septic systems?
Knox County has predominantly Minor components, Dewey, Corryton soils. The dominant drainage class is Well drained with hydrologic group B. The USDA rates 0% of surveyed soils as "Not Limited" for septic absorption fields, 25.5% as "Somewhat Limited", and 74.5% as "Very Limited".
How often should I pump my septic tank in Knox 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. With approximately 28,738 septic systems in Knox County, there are many local providers offering regular pumping services.
Can I install a conventional septic system in Knox County?
It depends on your specific site. USDA soil data shows that 74.5% of soils in Knox County are rated "Very Limited" for septic absorption fields, while only 0% are "Not Limited." This means many properties will require alternative systems such as mound systems, pressure distribution systems, or aerobic treatment units. A percolation test ($850-$1700) and soil evaluation are required before the county will approve a system design.
How long does a septic system last in Knox County?
A well-maintained septic system in Knox 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 (Knox County has predominantly well drained soils). Regular pumping every 3-5 years and avoiding excess water usage are the two most effective ways to extend system life.

Free Quote for Knox County

Get matched with licensed septic pros in your area. Free, no obligation.

Quick Facts

Population478,971
Est. Septic Homes28,738
Avg Pumping Cost$400
Drainage ClassWell drained
Septic SuitabilityVery limited

Common Septic Services

Pumping: $300-$550
Inspection: $200-$400
Repair: $700-$4,900
Installation: $5,600-$11,200

Data last updated: 2026-04-13