Septic, Perc Tests and Soil Evaluations for NC Land Sellers

Septic and soil evaluations: what NC land sellers need to know

By the They Buy Land team at Forma Home Builders · Updated October 18, 2026

If your land is not on public sewer, septic suitability may be the most important fact about it. Here is how North Carolina actually decides, and what it means for your price.

Short answer: North Carolina does not use a simple perc test anymore. The county health department (or an authorized private professional) does a soil and site evaluation. If suitable, the county issues an Improvement Permit, then a Construction Authorization, which is needed for a building permit. An unsuitable finding for one system type does not always rule out others.

Perc test vs soil and site evaluation

People still say "perc test," but in North Carolina the decision is based on a soil and site evaluation: soil depth and texture, wetness, slope, available space and setbacks. Statewide oversight is by the On-Site Water Protection Branch of the NC Division of Public Health, working with county health departments.

The permits, in order

Application to county environmental health, with a site plan or plat.
Soil and site evaluation. Many counties, including Union and Iredell, require the applicant to dig backhoe pits or provide a backhoe and operator.
Improvement Permit (IP). Approves the site and proposed system. Under G.S. 130A-336, a permit issued with a plat can be valid without expiration, while one issued with a site plan is valid for five years.
Construction Authorization (CA). Authorizes installation of a specific system and is required for a building permit. It can be issued with the IP.
Operation Permit after installation and inspection.

Private options

North Carolina law also allows an engineered option permit (G.S. 130A-336.1) and an Authorized On-Site Wastewater Evaluator option (G.S. 130A-336.2), where licensed professionals evaluate and design the system and file a notice with the county. These can help on complicated sites.

What a denial really means

An unsuitable finding means the site, as proposed, does not meet the rules for that system. It may still support a different system type (such as a pump to a better area, or an advanced pretreatment system), a different house location, a smaller house with fewer bedrooms, or a combination with an adjoining tract. Some land is truly unsuitable for septic, and then value depends on sewer access or other uses.

Should you get a septic permit before selling?

If you plan to list, a valid Improvement Permit can make a lot more attractive to retail buyers. It costs application fees, backhoe time and weeks of waiting, with no guarantee of approval. If you sell to us, you do not need to. We order evaluations as part of our due diligence and pay for them. Existing permits are a plus, so send them if you have them.

Have an old permit? Improvement Permits issued with a plat may still be valid years later. Send us a copy and we will check it.

Quick buildability checkTick what you know is true. Unsure? Leave it blank.

Road frontage on a public, state-maintained road (or a recorded, deeded easement) Public water at the road, or a good chance of a private well Public sewer nearby, or an existing septic Improvement Permit No mapped FEMA flood zone over the area you would build on No mapped wetlands or streams through the middle of the property Zoning allows homes (residential or agricultural that permits houses) Clear title: one owner, or all heirs and co-owners willing to sign Mostly gentle slope, not a steep ravine or rock outcrop

Tick a few boxes to see where your property stands.

This is a rough screen, not a determination. County environmental health, planning and the utility make the official calls, and we check them for you before making an offer.

Quick answers

Does NC still do perc tests?

Not in the old sense. Counties do a soil and site evaluation and issue an Improvement Permit if the site is suitable.

How long is a septic Improvement Permit valid in NC?

Under G.S. 130A-336, an IP issued with a plat can be valid without expiration; one issued with a site plan is valid for five years.

Will you buy land that was denied for septic?

Often, yes, priced for what it can support. A denial for one system is not always the final word.

Get a no-obligation offer

Tell us about the property. A local team member, not a call center, follows up directly. No fees, no pressure.

We are the end buyer, so the company that signs is the company that closes

No commissions, no repairs, no cleanup

A North Carolina or South Carolina closing attorney handles the closing

You choose the closing date

Prefer to talk? Call or text 704-980-0444