Water, Sewer & Septic

Soil Percolation (Perc) Test

Perc and deep hole soil testing to determine whether land can support a septic system, and what type. Typical US fees run $200 to $3,000 per test, and most projects take 1 to 4 weeks, seasonal in some states. Our drawings, calculations and reports are sealed by a Professional Engineer (PE) licensed in the state where your project is located, ready for permit submission.

Typical US fee$200 to $3,000per test

Typical timeline1 to 4 weeks, seasonal in some states

Permit drawingsSealed by a PE

What the work involves

A percolation test measures how fast water drains into soil; many jurisdictions also require deep hole test pits to inspect soil layers and the seasonal high water table. Tests may be performed by a septic contractor, soil scientist or engineer, often witnessed by the health department. Results determine whether a lot is buildable without sewer and what septic system it needs.

When you need it

Buying land without public sewer
Applying for a septic permit
Planning a lot split
Replacing a failed septic system

What you receive

Test hole logs
Perc rates
Soil evaluation report
Health department submission

What drives the cost

HomeGuide reports $200 to $1,500 for hand-dug tests and $500 to $3,000 or more for excavator tests; HomeAdvisor gives $750 to $1,900 (average $1,300). An engineer adds $200 to $500 per HomeGuide.

Related calculators

Septic Tank Size CalculatorEstimate a residential septic tank size from the number of bedrooms using a common 1,000 gallon minimum plus 250 gallons per extra bedroom.

Frequently asked questions

How much does soil Percolation (Perc) Test cost?

Across the US, soil Percolation (Perc) Test usually costs $200 to $3,000 per test. HomeGuide reports $200 to $1,500 for hand-dug tests and $500 to $3,000 or more for excavator tests; HomeAdvisor gives $750 to $1,900 (average $1,300). An engineer adds $200 to $500 per HomeGuide.

How long does soil Percolation (Perc) Test take?

Plan on 1 to 4 weeks, seasonal in some states from signed proposal to stamped deliverables, longer if a site visit, soil testing or a permit review cycle is involved.

Do I need a licensed PE for soil Percolation (Perc) Test?

In most US jurisdictions, yes. When the work needs a permit, the plans, calculations or report usually must be sealed by a Professional Engineer licensed in the state where the project is located. Every deliverable we issue for permit is sealed that way.

Will I also need a soil scientist?

Sometimes. Depending on the site, soil Percolation (Perc) Test can also involve a soil scientist, septic designer or health department. We tell you up front which other professionals your project needs and coordinate with them so the drawings agree.

Who do you provide soil Percolation (Perc) Test for?

Most of our clients for this service are homeowners, developers and lenders. Describe your project and one of our engineers will reply with scope, fee and schedule.

Can a lot fail a perc test?

Yes. Failed tests may mean an alternative system or that the lot cannot support septic.

Are perc tests seasonal?

Some jurisdictions only allow testing during wet seasons to capture high water tables. Ask your health department before scheduling.

Should I test before buying land?

Yes. Make the purchase contingent on passing results.

How many holes are needed?

It varies; HomeGuide notes a one-acre lot typically needs four to seven holes. The health department or designer sets the number and location.