Septic Systems in Cassia County, ID

Modeled costs, available official data & local verification guidance

Pop. 24,655 ~26.4% on septic ~2,604 septic homes

Our modeled range for septic pumping in Cassia County, Idaho is $300-$650. A modeled conventional installation range is $6,100-$12,200. The site model estimates approximately 2,604 homes may use septic systems; this is not a county count.

Septic System Costs in Cassia County

ServiceLowAverageHigh
Pumping / Cleaning$300$450$650
Routine Inspection$250$350$500
Real Estate Inspection$400$600$850
Minor Repair$750$1,100$5,300
Conventional Installation$6,100$8,700$12,200
Aerobic System Installation$11,450$16,350$22,900
Drainfield Replacement$6,100$8,700$12,200
Perc Test$900$1,300$1,800

Modeled estimates derived from national reference ranges and a regional multiplier, not observed local quotes. Actual costs depend on system type, site conditions, permits, and provider.

Groundwater & Water Table in Cassia County

Monitoring Wells
93
Avg Depth to Water
198.3 ft
Median Depth
163.7 ft
Shallowest Recorded
4.2 ft

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

Source: USGS National Water Information System. Based on 172 measurements from monitoring wells.

Septic System FAQ for Cassia County

How much does septic pumping cost in Cassia County?
Our modeled pumping range for Cassia County, Idaho is $300-$650, with a modeled midpoint of $450. This is not an observed local quote. Actual cost varies by tank size, access, travel distance and tank condition.
How much does a new septic system cost in Cassia County?
Our modeled conventional-installation range for Cassia County is $6,100-$12,200; the modeled aerobic-system range is $11,450-$22,900. These are planning indicators, not observed local quotes. A site evaluation and provider estimate are needed.
Do I need a permit for a septic system in Cassia County?
Permit requirements depend on the work, property and responsible authority. Review the verified official-source summary on this page, then contact the authority directly for the current application, exemptions, fees, site-evaluation requirements and inspection steps before work begins.
What soil types are in Cassia 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 Cassia 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 Cassia County?
A well-maintained septic system in Cassia 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.

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Quick Facts

Population24,655
Est. Septic Homes2,604
Avg Pumping Cost$450

Common Septic Services

Pumping: $300-$650
Inspection: $250-$500
Repair: $750-$5,300
Installation: $6,100-$12,200

Data last updated: 2026-08-26