What is a Perc Test?

Fixing and flipping a house means doing fun things, like adding demoing a kitchen, re-imagining the floor plan, and adding colorful paint to the wall.

But it also means doing dirty work, and this may include accessing the waste system. 

How can you tell if a septic system on a given property works well as is when you're previewing a property? Or, if a property is in an urban area and already connected a public sewer system, how can you tell if there are drainage issues?

This is where a perc test comes in.

But what is a perc test, and how can you conduct one?

In this article, we’ll break down everything you need to know about a perc test, including a simple 4 step process for doing one. And, we'll break down what a good result on a perc test is, along with a poor one.

Let’s get started! 

What is a Perc Test?

A perc test, short for percolation test, is a soil analysis that determines the rate at which water infiltrates into the ground. 

Why is this important for you as a real estate investor?

The results help evaluate the suitability of the soil for septic system installation or establishing drainage for a property. 

Poor soil permeability can lead to a host of issues, including: 

• drainage problems, 
• soil saturation, 
• potential health hazards, and 
• above all, a major problem with your property

For properties without access to a public sewer system, a septic system is typically required. A perc test determines whether or not the soil can handle the wastewater generated by a property.

But a perc test isn't only for properties in need of a septic system. Even for properties connected to a public sewer system, a perc test can help you understand the soil's permeability and whether or not there are any drainage issues that can prove costly down the road.

Plus, the results of a perc test can influence the design and placement of septic systems or drainage infrastructure on a property. By understanding the soil, you can set up the wastewater management now — and not deal with its costly effects down the road.

How Does a Perc Test Work?

Simply put, a perc test involves digging holes in the ground, filling them with water to simulate rainfall, and measuring the time it takes for water to seep into the soil through the bottom of the hole. 

The rate at which the water infiltrates the soil is then measured to determine its permeability.

How to Conduct a Perc Test

Now that we know what a perc test is and why it's important for real estate investors and home owners alike, let's take a look at how to conduct one, step by step.

Step 1: Dig test holes

In general, at least three test holes are dug on the property. The holes must be deep enough to reach below the anticipated depth of the drain field or septic system.

Step 2: Saturate the holes

After the holes are dug, they are filled with water and allowed to saturate overnight.

Step 3: Percolation measurements

The next day, the water level is measured, and the holes are filled with water again to a standard level. The time it takes for the water to drop a specific distance is recorded, providing the percolation rate of the soil.

Step 4: Calculation and interpretation

Based on the percolation rate, along with the local regulations, you can determine the soil's suitability for a septic system or drainage.

What Do Perc Test Results Mean?

Once a perc test is complete, the last step is to interpret the results.

Fast percolation rates suggest sandy or gravelly soil, which is ideal for septic systems. 

Slow percolation rates indicate clay or compacted soil, requiring alternative solutions to ensure proper drainage. It may indicate that water will not absorb efficiently or drain away from the site, which can lead to standing water, erosion, and potential property damage — all things that you don't want with your property.

How Much Does a Perc Test Cost?

Because the cost of a perc test comes down to how big the property is, the price can vary from one property to another. Here are a few general prices for how much a perc test costs.

• 0.25 acres – $150-$250
• 0.5 acres – $300-$500
• 1 acre – $600-$900
• 5 acres – $1100-$2000

The Bottom Line: Perc Test

Whether you're fixing and flipping a home, or building a house to live in or as an investment, a perc test is critical to address a given property's ability to handle wastewater and it's potential drainage issues.

By being proactive and determining this ahead of time, the simple cost of a perc test can save yourself time, money and stress now and in the future.

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