Septic Systems in Cass County, IL

Regulations, costs, soil data & local providers

Pop. 13,042 ~16.8% on septic ~876 septic homes Well drained soil

Septic pumping in Cass County, Illinois costs $300-$550 (avg $400). A new septic system installation costs $5,800-$11,600. USDA soil data rates 0% of county soils as suitable for septic absorption fields. Approximately 876 homes in this county use septic systems.

Septic System Costs in Cass County

ServiceLowAverageHigh
Pumping / Cleaning$300$400$550
Routine Inspection$200$300$400
Real Estate Inspection$400$550$750
Minor Repair$750$1,050$5,100
Conventional Installation$5,800$8,300$11,600
Aerobic System Installation$10,900$15,600$21,850
Drainfield Replacement$5,800$8,300$11,600
Perc Test$900$1,250$1,750

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

Soil & Septic Suitability in Cass County

Drainage Class
Well drained
Hydrologic Group
B
Unique Soil Types
76

Dominant Soil Types

Soil SeriesCoverageDrainageHydro Group
Fayette 470 Well drained B
Ambraw 396 Poorly drained C/D
Sawmill 387 Poorly drained B/D
Beaucoup 383 Poorly drained C/D
Arenzville 300 Well drained B

Septic Tank Absorption Field Suitability

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

Not Limited (Good)0%
Somewhat Limited17.7%
Very Limited82.3%

Overall rating: Very limited

Source: USDA NRCS Soil Survey Geographic Database (SSURGO)

Septic Regulations & Permits in Cass 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 Cass County health department for current permit requirements, fees, and approved system types.

Septic System FAQ for Cass County

How much does septic pumping cost in Cass County?
Septic pumping in Cass County, Illinois 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 Cass County?
A conventional septic system installation in Cass County typically costs $5,800-$11,600. An aerobic treatment unit (ATU) costs $10,900-$21,850. 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 Cass 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 Cass County health department for current requirements and fees.
What soil types are in Cass County and how do they affect septic systems?
Cass County has predominantly Fayette, Ambraw, Sawmill 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, 17.7% as "Somewhat Limited", and 82.3% as "Very Limited".
How often should I pump my septic tank in Cass 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 Illinois have mandatory pumping schedules — check with your local health department.
Can I install a conventional septic system in Cass County?
It depends on your specific site. USDA soil data shows that 82.3% of soils in Cass 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 ($900-$1750) and soil evaluation are required before the county will approve a system design.
How long does a septic system last in Cass County?
A well-maintained septic system in Cass 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 (Cass 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

Population13,042
Est. Septic Homes876
Avg Pumping Cost$400
Drainage ClassWell drained
Septic SuitabilityVery limited

Common Septic Services

Pumping: $300-$550
Inspection: $200-$400
Repair: $750-$5,100
Installation: $5,800-$11,600

Data last updated: 2026-04-13