If you are buying vacant land in Pender, Brunswick, or Onslow County, one question determines everything: “Does it perc?” In rural markets like Rocky Point, Hampstead, Maple Hill, and parts of Leland, municipal sewer isn’t an option. Your entire construction plan depends on whether the soil can support a septic system.

But in 2025, a “perc test” isn’t enough. North Carolina’s rules have evolved, soil evaluations are stricter, and timelines are longer. Before you put a non-refundable Due Diligence Fee on the line, here is the technical guide you need.

1. It’s Not a “Perc Test” Anymore

What most people still call a perc test is now a Soil & Site Evaluation.

• The Old Method: Dig a hole, pour water inside, measure drainage speed.
• The 2025 Method: A full profile analysis of soil texture, horizon depth, permeability, and seasonal high water table.

Why this matters: A lot may drain fine but still fail because the water table is too shallow—12–18 inches in parts of Brunswick County—disqualifying it for a standard system.

2. You Need Two Different Permits

North Carolina uses a two-step permitting process through each county’s Environmental Health Department.

Improvement Permit (IP)

Confirms the land is suitable for a specific number of bedrooms. Valid for 5 years (or indefinitely once recorded on a plat).

Important: An IP is not permission to install the system.

Construction Authorization (CA)

Shows the exact design of the system—tank placement, drain line layout, setbacks. You need this before you can pull a building permit.

Buyer Tip: If a seller provides a 2019 IP, check if it has expired. Many do. If it’s expired, you must start from scratch.

3. The “Private Soil Scientist” Shortcut

County backlogs are common—especially in Pender County, where growth is explosive.

• County Evaluation: ~$400, but wait times of 4–8 weeks are normal.
• Private Licensed Soil Scientist (LSS): $1,500–$2,500, with typical turnaround in 7–14 days.

When you need this: If your Due Diligence period is under 30 days, a private soil scientist may be the only way to protect your deposit.

4. System Types & Costs (The “Bad Soil” Tax)

Soil dictates system design, and design dictates cost.

• Conventional System: $4,000–$8,000
  Ideal sandy soils (Hampstead, Castle Hayne).
• Chamber / Accepted System: $5,000–$12,000
  Used on tighter lots or mixed soils.
• Low-Pressure Pipe (LPP) Engineered: $15,000–$25,000+
  Needed for clay soils (Maple Hill) or high water tables.
• Mound / Fill System: $25,000+
  Used when natural soil depth is insufficient—common in low-lying Brunswick areas.

Translation: The wrong soil can add $20k–$30k to your build budget overnight.

5. The “Repair Area” Deal Killer

NC law requires every lot to have:

• a primary septic area, and
• a full secondary (100%) repair area.

This is the most common reason small lots fail.

Example: A 0.5-acre lot may fit the house and a septic field, but if it cannot support the required repair field, the county will deny the permit.

Never assume a smaller lot is buildable until both areas are mapped.

The Bottom Line

A failed perc—or failed site evaluation—can wipe 95% off a land’s value. A “buildable lot” can become “recreational land” overnight.

At Aspyre Realty Group, we approach land like engineers. We connect you with private soil scientists, review expired permits, and ensure you know the true buildability before you commit.