If you’re planning to build a home or install a septic system, PERC testing is a crucial first step. PERC, short for percolation, is a test to measure how well the soil absorbs water. The test helps determine whether your land can support a traditional septic system or if alternative solutions are needed.

What Is PERC Testing?

PERC testing involves digging several holes in the soil and filling them with water to measure how quickly the water drains. The results, expressed in inches per hour, help engineers design a septic system that will efficiently treat wastewater. If the soil drains too slowly or too quickly, you might need an advanced or alternative septic system (House and Home Online)​ (FortuneBuilders).

Why Do You Need a PERC Test?

1. Regulatory Compliance: Most counties and municipalities require a PERC test for properties intended for residential or commercial development in areas without public sewer access.
2. Environmental Protection: An effective septic system prevents wastewater contamination of groundwater, making PERC testing essential for environmental safety.
3. Financial Impact: If the soil is unsuitable, alternative septic systems may be required, increasing project costs.
4. Property Value: Land that passes a PERC test is generally more desirable and valuable, as it’s ready for building. Failed tests may limit a property’s potential.

The PERC Testing Process: What to Expect

The PERC test itself typically involves a few key steps:

1. Site Selection: A licensed engineer or soil scientist identifies suitable spots to dig test holes, usually based on the planned septic system location.
2. Digging Test Holes: Several holes are dug at varying depths (typically 18 to 30 inches) to simulate where the septic system would sit.
3. Filling the Holes with Water: Each hole is filled with water, then observed over a period to measure the drainage rate.
4. Measuring Percolation Rates: The percolation rate, usually expressed in minutes per inch, is the critical result. Soils with moderate drainage are ideal, while those that drain too quickly or slowly may require alternative solutions.
5. Interpreting Results: If the results fall within an acceptable range, a conventional septic system may be feasible. If not, alternative systems like mound systems or aerobic systems may be necessary (House and Home Online)​ (FortuneBuilders).

How Much Does PERC Testing Cost?

PERC testing costs can vary widely, with several factors influencing the final price. On average, PERC testing costs between $300 and $1,000, but for more complex sites, the cost can increase up to $3,000 or more.

Key Cost Factors Explained:

1. Location: Urban areas may have higher testing costs due to increased demand and local regulations.
2. Soil Complexity: Rocky or clay-heavy soils require more extensive testing and specialized equipment, adding to the cost.
3. Property Size: Larger properties generally need more test points, increasing labor and time required, resulting in higher costs.
4. Labor Rates: Providers may charge either a flat rate or hourly rate, ranging between $100 and $250 per hour (FortuneBuilders).
5. Depth and Number of Test Holes: More test holes and greater depths increase both labor and equipment costs, influencing the final price (Bob Vila).

Alternative Septic Systems and Additional Costs

For properties that fail standard PERC tests, alternative septic systems may be required. These systems, such as mound or aerobic systems, can significantly increase installation costs, sometimes ranging from $10,000 to $40,000, depending on the technology and site requirements. It’s essential to consider these potential costs when budgeting for property development.

Tips for Managing PERC Testing Costs

• Request Multiple Quotes: Getting quotes from several providers can help you find the most cost-effective option without compromising on quality.
• Work with Local Experts: Local engineers or soil scientists are often familiar with the area’s soil conditions, which can lead to more accurate results and potentially save time and money.
• Plan Ahead: Knowing the type of septic system you may need and the local regulations can help you budget and avoid unexpected expenses.

Conclusion

PERC testing is an essential step in assessing land suitability for septic systems and ultimately for building. Although the test requires an upfront investment, it can save substantial costs and issues down the line by ensuring compliance and environmental safety. Before purchasing land, especially in rural areas without access to public sewer systems, understanding PERC test results and their implications is invaluable. Consulting local professionals and exploring alternative solutions if needed will help ensure your project is successful.

References:

House and Home Online, What Is Perc Testing and How Does It Work? 

FortuneBuilders, What Is a Perc Test & When Do You Need One?

Bob Vila, How Much Does a Perc Test Cost?