Guide · Perc test

Perc test cost by state

Q: What does a perc test tell you?

A perc test measures how fast water moves through soil at trench depth, in minutes per inch. This rate determines the application rate used to size your drainfield — the slower the soil, the larger the field required.

Q: Can a site fail a perc test?

Yes. Soil slower than 90 minutes per inch usually cannot support a conventional drainfield. A failing result typically means a mound system, aerobic treatment unit, or in some cases the lot cannot support any septic system.

Q: Do I need a perc test to build a house?

If the property needs a septic system rather than public sewer, yes. A soil evaluation or perc test is required in all 50 states before a septic permit can be issued.

Q: When should I get a perc test done?

Before you buy land. A failed result affects what you can build and what it costs. Many states require wet-season testing, so plan around that window.

A percolation test runs $150 to $1,500 depending on your state, soil conditions, and who performs the test. More importantly, the result controls the size and cost of the septic system you are allowed to build.

$150lowest state avg

$1,500highest state avg

50states covered

By state

Perc test cost by state — all 50 states

Prices reflect typical ranges for a standard residential percolation test or basic soil evaluation. Engineered evaluations run higher in every state.

State	Typical cost range	Test type required	Who performs it
Alabama	$200 – $600	Soil evaluation	Licensed soil classifier or ADPH evaluator
Alaska	$400 – $1,200	Engineered evaluation	Registered engineer (most sites)
Arizona	$250 – $700	Site investigation + perc	Certified professional
Arkansas	$200 – $500	Soil evaluation	Licensed Designated Representative
California	$400 – $1,500	Soil morphology + perc	Certified professional, county reviewed
Colorado	$300 – $900	Soil morphology	Registered professional engineer or soil scientist
Connecticut	$350 – $900	Deep test pits + perc	Licensed soil scientist, witnessed by local health
Delaware	$300 – $800	Soil evaluation	Licensed site evaluator
Florida	$250 – $700	Site evaluation (water table focus)	FDEP licensed professional
Georgia	$200 – $600	Soil classification	Health dept. staff or certified soil classifier
Hawaii	$500 – $1,500	Site evaluation	DOH approved professional
Idaho	$250 – $700	Perc + soil log	Health district staff or certified evaluator
Illinois	$250 – $700	Soil evaluation	Licensed professional sanitarian
Indiana	$300 – $800	Soil morphology	Registered soil scientist (required)
Iowa	$250 – $700	Soil morphology	Certified evaluator, county sanitarian
Kansas	$200 – $600	Perc or soil eval	County sanitarian
Kentucky	$200 – $600	Soil evaluation	Certified site evaluator or AOSE
Louisiana	$200 – $600	Site evaluation	Health dept. district sanitarian
Maine	$400 – $1,000	Full LSE evaluation	Licensed Site Evaluator (designs system too)
Maryland	$300 – $900	Soil morphology	Licensed soil scientist
Massachusetts	$500 – $1,500	Title 5 deep test pits + perc	Licensed soil evaluator, witnessed by local board
Michigan	$250 – $800	Set by county code	County health department (varies by county)
Minnesota	$300 – $900	Soil morphology	Licensed Certified Soil Tester
Mississippi	$200 – $500	Soil evaluation	Health dept. evaluator or certified professional
Missouri	$200 – $600	Soil morphology	Registered Onsite Soil Evaluator
Montana	$300 – $800	Soil morphology	Licensed evaluator, county health
Nebraska	$200 – $600	Soil evaluation	Certified environmental professional
Nevada	$300 – $800	Perc + soil log	NDEP or county health authority
New Hampshire	$400 – $1,000	Full NHDES evaluation	NHDES approved designer
New Jersey	$400 – $1,200	Soil logs + permeability	Licensed professional
New Mexico	$250 – $700	Perc or soil eval	NMED licensed professional
New York	$400 – $1,200	Soil evaluation	Licensed professional, county health review
North Carolina	$200 – $600	Soil morphology	County health dept. soil scientist
North Dakota	$200 – $600	Perc + soil log	Local health unit staff
Ohio	$250 – $700	Soil evaluation	Local health district staff
Oklahoma	$200 – $500	Soil profile evaluation	Licensed professional sanitarian
Oregon	$300 – $900	Site evaluation	DEQ or contract county evaluator
Pennsylvania	$300 – $900	Perc + soil log	Sewage Enforcement Officer (SEO)
Rhode Island	$400 – $1,000	Soil evaluation	RIDEM licensed designer
South Carolina	$200 – $600	Site evaluation	DES regional staff
South Dakota	$200 – $600	Perc or soil eval	Licensed professional
Tennessee	$200 – $600	Soil evaluation	TDEC certified evaluator
Texas	$250 – $700	Site evaluation	Licensed Professional Sanitarian or PE
Utah	$250 – $700	Perc + soil log	Local health department
Vermont	$400 – $1,000	Full DEC evaluation	Licensed designer (combined water + wastewater)
Virginia	$300 – $900	Soil morphology	AOSE (Authorized Onsite Soil Evaluator)
Washington	$300 – $900	Soil morphology	Licensed soil scientist or designer
West Virginia	$200 – $600	Perc + site eval	Local health department
Wisconsin	$300 – $800	Soil morphology	Licensed Certified Soil Tester
Wyoming	$250 – $700	Perc or soil eval	DEQ or delegated county

Note: These are typical ranges for standard residential evaluations. Engineered evaluations, complex sites, and wet-season scheduling requirements can push costs above the high end shown. Confirm with your local health department before budgeting.

Summary

What drives perc test cost

Highest cost states

MA, CA, HI, NH, VT

Strict evaluation requirements, licensed professionals mandatory, wet-season scheduling.

Lowest cost states

AL, AR, MS, OK, SD

Simpler perc test accepted, county health staff perform evaluations.

Biggest cost factor

Who must do it

States requiring a licensed soil scientist or PE cost 2-3x more than county staff evaluations.

Hidden cost

Wet season timing

Scheduling delays add weeks. In some states tests are only valid Oct-April.

What a perc test actually measures

A percolation test measures how fast water drains through soil at trench depth — typically 18 to 36 inches below grade. The result is in minutes per inch: how long it takes for water to drop one inch. Slow rates mean tight soil. Fast rates mean permeable soil.

That rate feeds directly into drainfield sizing. A site at 20 min/inch needs roughly twice the absorption area of a site at 10 min/inch, for the same house. At 90 min/inch, a conventional drainfield is usually not permitted.

How the result affects your system cost

Perc rate	Soil type	Field size (3 BR)	System required	Extra cost vs. good soil
5 – 30 min/inch	Sand / sandy loam	560 – 750 sq ft	Conventional gravity	—
31 – 60 min/inch	Loam / silt loam	1,000 – 1,500 sq ft	Conventional or pressure dosed	$1,500 – $4,000
61 – 90 min/inch	Clay loam	2,250 sq ft	Mound or advanced treatment	$8,000 – $18,000
Over 90 min/inch	Clay	Not permitted	Mound, aerobic, or holding tank	$15,000 – $30,000+

Perc test vs. soil morphology evaluation

Many states have moved away from the classic perc test toward a full soil profile evaluation. An evaluator digs a pit, reads the soil layers, and records texture, structure, and water table signs. It costs more but gives a more reliable answer — a single timed hole on one afternoon can miss seasonal groundwater that governs the whole design.

When to get one

Before you buy land — if the property needs septic. A result that rules out a conventional system changes what the lot is worth. Discovering this after closing is expensive with no clean solution. Many states require wet-season testing, so check the window for your state before scheduling.

Verify locally. Perc test requirements, acceptable rates, and who may conduct the test are set by your state and county. The figures here are typical ranges — your local health department is the authority for your specific parcel.

Questions

Perc test questions answered

How much does a perc test cost?

A percolation test typically costs $150 to $500 for a basic test, or $400 to $1,500 for a full soil morphology evaluation. The range depends on your state, how many test holes are required, and whether a licensed soil scientist or engineer must witness the test.

What does a perc test tell you?

A perc test measures how fast water moves through the soil at trench depth, reported in minutes per inch. This rate sets the application rate used to size your drainfield — the slower the rate, the larger the field required. It is the single number that controls most of your septic design and cost.

Can a site fail a perc test?

Yes. Soil slower than 90 minutes per inch typically cannot support a conventional drainfield. A failing result usually means a mound system, an aerobic treatment unit, or in some cases no permitted system is feasible. This is why testing before you buy land matters so much.

Do I need a perc test to build a house?

If the property will use a septic system, yes — a soil evaluation or perc test is required in all 50 states before a septic permit can be issued. It is one of the first steps, before any design work.

When should I get a perc test done?

Before you buy land. Many states also require wet-season testing. Check with your state or county health department for the required timing window in your area.

How long is a perc test valid?

Most states accept a perc test result for two to five years. After that, a new test is required before a permit will be issued. If you are buying land with an existing report, confirm it is still within the validity period.

What is the difference between a perc test and a soil evaluation?

A perc test measures drainage speed in a single hole on one day. A soil morphology evaluation involves a licensed evaluator reading the full soil profile — texture, structure, colour, and features that show the seasonal high water table. The profile evaluation costs more but gives a more reliable result. Many states now require it instead of a simple perc test.

Next step

Know your perc rate — size your system

Enter your test result into the drainfield calculator to see exactly how much absorption area your site requires.

Calculator