Septic Systems in Twin Falls County, ID

Modeled costs, available official data & local verification guidance

Pop. 90,046 ~22% on septic ~7,924 septic homes

Our modeled range for septic pumping in Twin Falls County, Idaho is $300-$650. A modeled conventional installation range is $6,450-$12,900. The site model estimates approximately 7,924 homes may use septic systems; this is not a county count.

Septic System Costs in Twin Falls County

ServiceLowAverageHigh
Pumping / Cleaning$300$450$650
Routine Inspection$250$350$500
Real Estate Inspection$450$650$900
Minor Repair$800$1,150$5,600
Conventional Installation$6,450$9,200$12,900
Aerobic System Installation$12,100$17,250$24,150
Drainfield Replacement$6,450$9,200$12,900
Perc Test$1,000$1,400$1,950

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 Twin Falls County

Monitoring Wells
70
Avg Depth to Water
141.6 ft
Median Depth
102.8 ft
Shallowest Recorded
8.7 ft

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

Source: USGS National Water Information System. Based on 130 measurements from monitoring wells.

Septic System FAQ for Twin Falls County

How much does septic pumping cost in Twin Falls County?
Our modeled pumping range for Twin Falls 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 Twin Falls County?
Our modeled conventional-installation range for Twin Falls County is $6,450-$12,900; the modeled aerobic-system range is $12,100-$24,150. 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 Twin Falls 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 Twin Falls 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 Twin Falls 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 7,924 septic systems in Twin Falls County, there are many local providers offering regular pumping services.
How long does a septic system last in Twin Falls County?
A well-maintained septic system in Twin Falls 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.

Request a Local Availability Review

Tell us what you need. We will review the request and may connect you with a relevant provider where one is available. Submission does not guarantee a match or quote.

Quick Facts

Population90,046
Est. Septic Homes7,924
Avg Pumping Cost$450

Common Septic Services

Pumping: $300-$650
Inspection: $250-$500
Repair: $800-$5,600
Installation: $6,450-$12,900

Data last updated: 2026-08-26