Septic Systems in McLean County, IL

Regulations, costs, soil data & local providers

Pop. 170,954 ~9% on septic ~6,154 septic homes Well drained soil

Septic pumping in McLean County, Illinois costs $300-$650 (avg $450). A new septic system installation costs $6,150-$12,300. USDA soil data rates 1% of county soils as suitable for septic absorption fields. Approximately 6,154 homes in this county use septic systems.

Septic System Costs in McLean County

ServiceLowAverageHigh
Pumping / Cleaning$300$450$650
Routine Inspection$250$350$500
Real Estate Inspection$400$600$850
Minor Repair$750$1,100$5,400
Conventional Installation$6,150$8,800$12,300
Aerobic System Installation$11,550$16,500$23,100
Drainfield Replacement$6,150$8,800$12,300
Perc Test$900$1,300$1,800

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

Soil & Septic Suitability in McLean County

Drainage Class
Well drained
Hydrologic Group
C
Unique Soil Types
79

Dominant Soil Types

Soil SeriesCoverageDrainageHydro Group
Plano 368 Well drained B
Miami 362 Moderately well drained C
Catlin 342 Moderately well drained C
Saybrook 337 Moderately well drained C
Birkbeck 285 Moderately well drained C

Septic Tank Absorption Field Suitability

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

Not Limited (Good)1%
Somewhat Limited11.5%
Very Limited87.6%

Overall rating: Very limited

Source: USDA NRCS Soil Survey Geographic Database (SSURGO)

Groundwater & Water Table in McLean County

Monitoring Wells
12
Avg Depth to Water
12.1 ft
Median Depth
6.3 ft
Shallowest Recorded
0.4 ft Shallow Risk

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

Source: USGS National Water Information System. Based on 129 measurements from monitoring wells.

Septic Regulations & Permits in McLean County

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

Septic System FAQ for McLean County

How much does septic pumping cost in McLean County?
Septic pumping in McLean County, Illinois typically costs between $300 and $650, with an average of $450. 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 McLean County?
A conventional septic system installation in McLean County typically costs $6,150-$12,300. An aerobic treatment unit (ATU) costs $11,550-$23,100. 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 McLean County?
Yes. Virtually all counties in Illinois 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 McLean County health department for current requirements and fees.
What soil types are in McLean County and how do they affect septic systems?
McLean County has predominantly Plano, Miami, Catlin soils. The dominant drainage class is Well drained with hydrologic group C. The USDA rates 1% of surveyed soils as "Not Limited" for septic absorption fields, 11.5% as "Somewhat Limited", and 87.6% as "Very Limited".
How often should I pump my septic tank in McLean 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 6,154 septic systems in McLean County, there are many local providers offering regular pumping services.
Can I install a conventional septic system in McLean County?
It depends on your specific site. USDA soil data shows that 87.6% of soils in McLean County are rated "Very Limited" for septic absorption fields, while only 1% 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 ($900-$1800) and soil evaluation are required before the county will approve a system design.
How long does a septic system last in McLean County?
A well-maintained septic system in McLean 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 (McLean 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.

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Quick Facts

Population170,954
Est. Septic Homes6,154
Avg Pumping Cost$450
Drainage ClassWell drained
Septic SuitabilityVery limited

Common Septic Services

Pumping: $300-$650
Inspection: $250-$500
Repair: $750-$5,400
Installation: $6,150-$12,300

Data last updated: 2026-04-13