If you’re building a home in rural Oklahoma or considering buying land outside of city limits, you’ve probably heard the term “perc test.” But what exactly is a perc test, and do you actually need one here in Oklahoma?
Let’s break it down.
What is a Perc Test?
“Perc test” is short for percolation test. It measures how quickly water drains through the soil – a critical piece of information for designing a septic system. In states where perc tests are common, a hole is dug, filled with water, and timed to see how fast the water absorbs into the ground.
The idea is simple: soil that drains too slowly can flood a septic system, and soil that drains too fast might not treat wastewater properly.
What's Up With a Soil Profile?
Here’s where things get interesting. In Oklahoma, the state doesn’t rely on traditional perc tests for septic system approval. Instead, the Oklahoma Department of Environmental Quality (DEQ) prefers a soil profile test for most new installations.
Why a Soil Test Instead of a Perc Test?
Because Oklahoma has diverse and challenging soils – red clay, shale, rocky sand, and everything in between. A soil profile test gives a more complete picture of how your soil will behave in all seasons, not just on one day.
The results of a perc test can vary depending on how much rain the area has received recently, how hot it is the day of the test or, most importantly, if the pre-soak period was done correctly.
Soil Profile vs. Perc Test: What’s the Difference?
Test Type
How it Works
Used in Oklahoma?
Soil Profile Test
A licensed professional examines layers of soil for texture, color, structure, and signs of water saturation
Yes, preferred by the DEQ
Perc Test
Times how fast water drains in a test hole.
Yes but discouraged by the DEQ and difficult to find someone that still does them.
Do I Need A Soil Test?
Maybe – if you’re installing a new conventional septic system in Oklahoma, you will need a soil test. There are also other cases where they are required or recommended.
So if you’re:
- Building a new home,
- Buying land with no existing system,
- Replacing a failed septic system,
- Or, wanting to reduce the size of your aerobic spray
…let us advise you if you’ll need a soil profile evaluation by a certified soil profiler (like us!).
How Cyclone Septics Can Help
We handle everything in-house – soil profiling, system design, permits, installation, and even pumping and maintenance years down the road. No third-party delays. No confusion. Just honest answers and top-tier work.
Give us a call to schedule your soil test or get a consultation.
You can learn more about your septic system by purchasing Living With an Onsite Wastewater System on Amazon.
