Septic Systems in Johnson County, MO

Regulations, costs, soil data & local providers

Pop. 54,013 ~25% on septic ~5,401 septic homes Moderately well drained soil

Septic pumping in Johnson County, Missouri costs $250-$500 (avg $350). A new septic system installation costs $5,050-$10,100. USDA soil data rates 0% of county soils as suitable for septic absorption fields. Approximately 5,401 homes in this county use septic systems.

Septic System Costs in Johnson County

ServiceLowAverageHigh
Pumping / Cleaning$250$350$500
Routine Inspection$200$250$350
Real Estate Inspection$350$500$700
Minor Repair$650$900$4,400
Conventional Installation$5,050$7,200$10,100
Aerobic System Installation$9,450$13,500$18,900
Drainfield Replacement$5,050$7,200$10,100
Perc Test$750$1,100$1,550

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

Soil & Septic Suitability in Johnson County

Drainage Class
Moderately well drained
Hydrologic Group
C
Unique Soil Types
85
Avg Bedrock Depth
2.7 ft

Dominant Soil Types

Soil SeriesCoverageDrainageHydro Group
Winfield 410 Moderately well drained C
Barco 381 Well drained C
Mandeville 372 Well drained C
Sampsel 305 Poorly drained C/D
Greenton 303 Somewhat poorly drained D

Septic Tank Absorption Field Suitability

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

Not Limited (Good)0%
Somewhat Limited0%
Very Limited100%

Overall rating: Very limited

Source: USDA NRCS Soil Survey Geographic Database (SSURGO)

Groundwater & Water Table in Johnson County

Monitoring Wells
2
Avg Depth to Water
161.7 ft
Median Depth
155.9 ft
Shallowest Recorded
142.9 ft

Water table depths in this county are generally favorable for conventional septic systems.

Source: USGS National Water Information System. Based on 43 measurements from monitoring wells.

Septic Regulations & Permits in Johnson County

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

Septic System FAQ for Johnson County

How much does septic pumping cost in Johnson County?
Septic pumping in Johnson County, Missouri typically costs between $250 and $500, with an average of $350. 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 Johnson County?
A conventional septic system installation in Johnson County typically costs $5,050-$10,100. An aerobic treatment unit (ATU) costs $9,450-$18,900. Given the predominantly moderately 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 Johnson County?
Yes. Virtually all counties in Missouri 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 Johnson County health department for current requirements and fees.
What soil types are in Johnson County and how do they affect septic systems?
Johnson County has predominantly Winfield, Barco, Mandeville soils. The dominant drainage class is Moderately well drained with hydrologic group C. The USDA rates 0% of surveyed soils as "Not Limited" for septic absorption fields, 0% as "Somewhat Limited", and 100% as "Very Limited".
How often should I pump my septic tank in Johnson 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 5,401 septic systems in Johnson County, there are many local providers offering regular pumping services.
Can I install a conventional septic system in Johnson County?
It depends on your specific site. USDA soil data shows that 100% of soils in Johnson 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 ($750-$1550) and soil evaluation are required before the county will approve a system design.
How long does a septic system last in Johnson County?
A well-maintained septic system in Johnson 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 (Johnson County has predominantly moderately well drained soils). Regular pumping every 3-5 years and avoiding excess water usage are the two most effective ways to extend system life.

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Quick Facts

Population54,013
Est. Septic Homes5,401
Avg Pumping Cost$350
Drainage ClassModerately well drained
Septic SuitabilityVery limited

Common Septic Services

Pumping: $250-$500
Inspection: $200-$350
Repair: $650-$4,400
Installation: $5,050-$10,100

Data last updated: 2026-04-13