Who can do a perc test in Alabama?

ADPH states that soil testing must be performed by a professional engineer, professional land surveyor, professional geologist, or professional soil classifier. The local county health department environmentalist can also perform soil testing, or may hold results from previous tests on the property.

What happens if my lot fails the perc test?

It does not automatically mean you cannot build. ADPH states that where a site is unsuitable, an engineer must design a system that will properly treat the wastewater. EPA documents mound systems, chamber systems, and aerobic treatment units as designs intended for shallow soils, high groundwater, and constrained lots.

How much does a perc test cost in Alabama?

Cost varies by who performs it and how much testing the site needs, and it is not published by ADPH or the county health departments. Call your county environmental office first, since they may already have a previous soil test on file for the property.

Do I need a perc test before buying land?

If the lot has no municipal sewer access and no existing approved system, the soil evaluation is what determines whether it can be built on. Checking sewer availability and asking the county whether prior soil tests exist are both worth doing before closing.

Perc Tests and Soil Evaluation in Alabama

Updated 2026-08-11

Before you can put a septic system on a piece of Alabama land, somebody has to prove the ground can treat wastewater. That is what a perc test is for, and it is the step that decides whether a lot is buildable at all.

It is also the step people skip before buying land, which is how you end up owning acreage you cannot build on.

Check for sewer first

ADPH's first instruction is not about soil at all. Before anything else, check with the city sewer authority or the local health department to find out whether the property is near or eligible for municipal sewer service.

If sewer is available, the whole onsite question goes away. It is a five-minute phone call that occasionally saves several thousand dollars.

Who is allowed to perform the test

This is the part most people get wrong. In Alabama the soil testing has to be done by a qualified professional, and ADPH names the categories specifically:

A professional engineer
A professional land surveyor
A professional geologist
A professional soil classifier

Your county may be able to do it, or already have

ADPH also states that the local county health department environmentalist can perform soil testing, or may have information on previous soil tests for the property.

That second half is worth a phone call before you pay anyone. If the lot was tested before, the county may already hold the result, and a previous evaluation tells you what you are walking into. Cullman County's environmental office is at (256) 734-1030. Talladega County runs two branches: Talladega at (256) 315-4886 and Sylacauga at (256) 249-3807.

What actually makes a lot fail

ADPH describes the problem conditions plainly. Soils that are very shallow, drain too slowly, or are too wet may not support a conventional septic system. Lots that are simply too small can fail for space reasons alone, regardless of soil quality.

Shallow bedrock is a real factor in parts of this region. Around Sylacauga, where the marble belt runs, limited soil depth is a genuine constraint rather than a theoretical one.

Failing is not always the end

If the site is unsuitable for a conventional system, ADPH says an engineer must design a septic system that will properly treat the wastewater coming from the home. That usually means an alternative system rather than no system.

EPA documents several designs made for exactly these conditions: mound systems for shallow soil depth, high groundwater, or shallow bedrock; chamber systems for high water tables; and aerobic treatment units for smaller lots and inadequate soil conditions. They cost more and most require ongoing maintenance, but they exist.

ADPH is blunt about the cost of getting this wrong: raw sewage backing up in the home, surfacing in the yard, and potentially contaminating groundwater.

Then the permit

Once the evaluation is done, an Application for a Permit to Install an Onsite Sewage Disposal System goes to the county health department. ADPH approves it when the application and plans are complete and meet all the requirements of the rules, meaning Chapter 420-3-1.

Whoever installs the system must be licensed by the Alabama Onsite Wastewater Board. You can check any licensee yourself on the board's public roster before work starts.

Common questions

Who can do a perc test in Alabama?: ADPH states that soil testing must be performed by a professional engineer, professional land surveyor, professional geologist, or professional soil classifier. The local county health department environmentalist can also perform soil testing, or may hold results from previous tests on the property.
What happens if my lot fails the perc test?: It does not automatically mean you cannot build. ADPH states that where a site is unsuitable, an engineer must design a system that will properly treat the wastewater. EPA documents mound systems, chamber systems, and aerobic treatment units as designs intended for shallow soils, high groundwater, and constrained lots.
How much does a perc test cost in Alabama?: Cost varies by who performs it and how much testing the site needs, and it is not published by ADPH or the county health departments. Call your county environmental office first, since they may already have a previous soil test on file for the property.
Do I need a perc test before buying land?: If the lot has no municipal sewer access and no existing approved system, the soil evaluation is what determines whether it can be built on. Checking sewer availability and asking the county whether prior soil tests exist are both worth doing before closing.