How Does a PERC Test Work? Step-by-Step Explanation
Learn how soil percolation tests determine a property’s septic potential and what results mean for investors.
Austin Beverigde
Tennessee
, Goliath Teammate
If you're facing issues with your septic system or are planning to install one, understanding how a PERC test works is crucial. This test determines the soil's ability to absorb water, which is essential for the proper functioning of a septic system. Let’s break down the process so you can navigate it with confidence.
Quick Answer:
A PERC test, or percolation test, assesses how quickly soil absorbs water. The process involves digging test holes, filling them with water, and measuring the rate of absorption. This helps determine the suitability of the land for a septic system installation.
What is a PERC Test?
A PERC test measures the percolation rate of soil, which is how quickly water moves through the soil layers. This rate is crucial for designing a septic system that effectively treats wastewater. Knowing the percolation rate helps ensure that the septic system will function properly without causing environmental issues.
Steps to Conduct a PERC Test
Step 1: Locate the Test Area
Choose a suitable location for the test, ideally where the septic system will be installed. This area should be away from trees and structures to avoid interference with the soil's absorption capabilities.
Step 2: Dig Test Holes
Dig holes that are typically 6 to 12 inches wide and 12 to 24 inches deep. The number of holes required may vary based on local regulations, but generally, two to four holes are sufficient for a standard test.
Step 3: Saturate the Holes
Fill the holes with water to saturate the soil. This is usually done the day before the actual test to allow the soil to absorb water fully. Ensure the water level remains consistent for accurate results.
Step 4: Measure the Percolation Rate
After the soil has been saturated, refill the holes with water to a specific level (usually about 12 inches). Start a timer and measure how long it takes for the water to drop by one inch. Repeat this process three times and calculate the average absorption rate.
Step 5: Analyze the Results
The results will indicate whether the soil is suitable for a septic system. A faster absorption rate (less than 30 minutes per inch) typically indicates good drainage, while slower rates may require alternative systems or additional treatment methods.
Costs Associated with a PERC Test
The cost of a PERC test can vary widely based on location and soil conditions. On average, you might expect to pay between $300 and $1,000. Factors influencing the cost include:
Local regulations and requirements
Soil type and complexity of the site
Professional fees if hiring a contractor
Tools Needed for a PERC Test
If you're planning to conduct a PERC test yourself, here are the basic tools you'll need:
Shovel or post-hole digger
Measuring tape
Water source (hose or bucket)
Timer or stopwatch
Notebook for recording results
Timeline for a PERC Test
Conducting a PERC test can typically be completed in one day, but the entire process may take longer depending on the saturation phase. Here’s a rough timeline:
Day 1: Digging holes and saturating them with water
Day 2: Performing the actual test
Day 3: Analyzing results and making decisions
Alternatives to a PERC Test
If a PERC test indicates that your soil is not suitable for a traditional septic system, consider these alternatives:
Constructed wetlands
Sand filters
Composting toilets
Checklist for Conducting a PERC Test
Choose the right location for the test.
Dig the appropriate number of holes.
Saturate the holes with water a day before testing.
Measure the water absorption accurately.
Record all results for analysis.
Common Mistakes to Avoid
When conducting a PERC test, be mindful of these common mistakes:
Not saturating the holes properly, which can lead to inaccurate results.
Failing to dig holes deep enough, affecting the absorption rate.
Not measuring the water level consistently during the test.
Ignoring local regulations regarding testing procedures.
FAQs
What is the purpose of a PERC test?
A PERC test determines how well soil can absorb water, which is essential for the design and installation of a septic system. It helps identify suitable locations for wastewater disposal.
How long does a PERC test take?
The actual testing process can take a few hours, but the preparation, including saturating the holes, may require an additional day. Overall, expect the entire process to take about two to three days.
Can I perform a PERC test myself?
Yes, you can conduct a PERC test yourself if you have the right tools and knowledge. However, hiring a professional is recommended for accurate results and compliance with local regulations.
What happens if my soil fails the PERC test?
If your soil fails the PERC test, it may not be suitable for a traditional septic system. You may need to explore alternative wastewater treatment options or improve the soil conditions.
How often should a PERC test be done?
A PERC test is typically done once when installing a new septic system. However, if significant changes occur in the land or if the system fails, retesting may be necessary.
