I want to preface this by saying that I am a Land Professional in the Lowcountry of South Carolina, and this process may differ in other states or regions. Consult a local expert for state-specific information. 

One of the most common questions I get when selling land suitable for building a home is: “Does it perc?” While this is an excellent and important question to ask before purchasing property, the answer isn’t always as clear-cut as many buyers expect.

What is a Perc Test?

A percolation test, often referred to as a “perc test,” is used to determine how quickly water is absorbed into the soil. The purpose of this test is to evaluate whether the soil on a property is suitable for a septic system to properly dispose of wastewater from a home.

Although the term perc test is still widely used, the traditional method of digging a hole and pouring water into it to observe absorption rates is rarely used today. Modern evaluations typically involve a more comprehensive soil analysis performed by professionals to determine whether the land can support a conventional septic system. While approval for a conventional system is the ideal outcome, a property “not percing” doesn’t always mean what people think it does.

Why Do You Need a Perc Test?

When someone says, “The land doesn’t perc,” buyers are often immediately alarmed and assume that means they won’t be able to build a house on the property. While that can be true in certain situations, it is often not the case. In many instances, it simply means the property requires an engineered septic system instead of a conventional one.

Differences Between Engineered and Conventional Septic Systems

An engineered septic system is a custom-designed, high-performance wastewater treatment solution used when conventional systems are not feasible due to factors such as poor soil conditions, high groundwater levels, or limited usable space.

While engineered systems serve the same purpose of safely disposing of wastewater, there are both pros and cons to this approach. The primary downside is cost. Engineered systems are generally more expensive than conventional systems because they require a licensed engineer to design and draw site-specific plans that carefully control how wastewater is dispersed into the soil. The price difference can vary significantly depending on soil conditions and the complexity of the design.

The upside, however, is that engineered systems are tailored specifically to the property. In some cases, they can even perform more efficiently than conventional systems in challenging or marginal soil conditions.

For buyers, understanding this distinction is critical. Asking whether a property percs is always a smart move, but a property that doesn’t perc does not automatically need to be a deal breaker. Before deciding to move forward or walk away, it’s wise to consult with a septic installer or engineer to fully understand the cost difference between a conventional system and the engineered system required for that specific property.

If you’ve got questions about a perc test on your South Carolina land, get in touch with me at Aland@NationalLand.com or reach out to your local Land Professional today!