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Highlights
- A percolation (perc) test has a typical cost range of $750 to $1,850, with customers nationally paying an average of $1,300.
- Factors affecting the total cost of a perc test include the land size, hole size, land use, accessibility, labor, and permits.
- A homeowner who wants to install a septic system will typically be required by their local municipality to have a perc test performed.
- Since a perc test is a requirement in most municipalities for homeowners who need to install a septic system, a certified professional must complete the test for it to be valid.
A percolation test, also known as a perc test, is a type of soil test used to measure the water infiltration rate in soil. It is typically used to determine the suitability of a site for a septic system or another type of on-site wastewater treatment system. The test involves digging a hole in the ground and measuring the amount of time it takes for water to move through the soil. The results are then used to design an efficient septic system.
The cost of a perc test can vary depending on the location and size of the property. According to HomeAdvisor, a perc test costs between $750 and $1,850, with a national average cost of $1,300. This guide will cover the different factors involved in calculating perc test cost, reasons to get this type of test, tips on saving money on testing, and questions to ask a contractor about perc testing.
What Is a Perc Test?
A perc test is used to determine how quickly the soil at a testing site absorbs water. This soil assessment is then used to determine if a specific location is suitable for a septic system and, if so, to calculate the leach field’s size and design.
There are several steps a contractor will take when conducting a perc test. First, they will dig one or multiple hole(s) in an area that is representative of the soil type where a septic system will be installed. Then, depending on the soil composition, they’ll add several inches of gravel to the bottom of the hole. Following that, the contractor will saturate the soil to replicate a worst-possible drainage situation, and then fill the hole with water and measure the starting water level in the hole. Finally, they will wait for the water to drain out of the hole. As the water drains, the contractor will measure the water levels at regular intervals.
The rate of water infiltration can be determined by calculating the difference between the starting and final water levels and dividing by the time it took for the water to drain out of the hole.
Factors in Calculating Perc Test Cost
Perc tests are a crucial part of the process of determining whether a property is suitable for a septic system. Knowing the cost associated with these tests is important for homeowners and contractors alike. A perc test cost depends on several factors, including the following.
Land Size
Land size can significantly influence the cost of a perc test. The more land there is, the more holes will likely need to be dug, and more labor will be required to conduct the test. In addition, more equipment may be necessary to cover a larger area. This can also increase the cost of the test.
It’s important for homeowners to note that each state has unique requirements about how much testing needs to be completed based on land size, so depending on the state in which the land is located, lots equal in size may not require the same number of holes.
Additionally, if the land contains any slopes or other difficult terrain, which may be more common on a larger plot and also in some states more than others, more resources may be necessary to complete the test, further increasing the cost.
| Size of Lot | Cost Range |
| ¼ Acre | $150 to $1,000 |
| ½ Acre | $150 to $1,750 |
| ¾ Acre | $300 to $2,300 |
| 1 Acre | $450 to $3,000 |
Hole Size
The size of the hole for a perc test has a direct influence on the final cost. Wider and deeper holes require more digging, filling, and compacting than smaller holes. The extra time and work involved increase the cost of a septic perc test. If a large hole requires the use of a backhoe, a homeowner can expect the test price to increase by at least $200.
The following chart of typical hole sizes and the associated costs for a perc test if two holes are dug on the testing site.
| Hole Size | Cost Range |
| 6 inches by 2 feet | $675 to $800 |
| 2 feet by 2 feet | $800 to $950 |
| 2 feet by 3 feet | $900 to $1,200 |
| 3 feet by 4 feet | $1,175 to $1,550 |
| 3 feet by 5 feet | $1,250 to $1,800 |
| 3 feet by 6 feet | $1,400 to $2,000 |
Land Use
Perc prices can be significantly influenced by how a homeowner intends to use the land being tested. For example, a perc test for a septic system will typically be more expensive than a perc test for a drainage system because a septic system requires a deeper test to ensure that the soil is suitable.
A perc test on land in an urban area may cost more due to increased regulation and the need for more extensive testing. Additionally, if the land is being used for agricultural or forestry purposes, a more in-depth assessment may be necessary to ensure that the soil is suitable.
Accessibility
A property can be difficult to access for a perc test if it has a lot of trees, dense vegetation, steep or wet terrain, or a lot of underground utilities. Additionally, if the property is located in a remote or hard-to-reach area, it could be difficult for a perc test crew to travel to the test site.
The cost of a perc test may vary depending on the accessibility of the test site. If the test site is difficult to access due to terrain, the cost may be higher to accommodate the need for additional machinery and time to access the site. Conversely, if the test site is easy to access, the cost may be lower.
Labor
Labor costs for a septic tank perc test can vary from one municipality to the next, though the average rate is usually around $100 to $250 per hour. Some professionals charge a starting rate or flat fee of $300, especially if the test is simpler in nature.
Generally, a perc test can take anywhere from 24 to 48 hours to complete, though not all the hours are billable. A perc test requires more labor hours and so will cost more when the soil conditions are difficult to access or when the area being tested is larger. Other factors, such as the type of soil and the depth of the test, can also affect the amount of labor required for a perc test.
Additional Costs and Considerations
It is important for homeowners to keep the following potential factors in mind when budgeting for a perc test. This way, they can ensure they have enough funds to cover any unexpected costs.
Permits and Inspection
Most local governments do not require a permit to conduct a perc test. However, if the test results show that the soil is suitable for a septic system, a permit will be required to install the system. This permit ensures that the proposed septic system meets local safety and health regulations, as well as any other applicable laws.
The process for obtaining a permit usually involves submitting an application to the local government, along with a site plan and a detailed description of the proposed septic system. Once the application is approved, a permit for the installation of the septic system will be issued. For a septic system, permits run anywhere from $320 to $1,880. Many times, a contractor will secure the permit, but the homeowner will want to check and make sure.
Technician Fees
Technician fees can significantly impact the cost of a perc test, depending on the type of technician required. A licensed engineer typically designs, evaluates, and supervises the construction of engineering projects. They are also certified to conduct perc testing to determine the soil’s ability to absorb wastewater. A licensed engineer fee can add an additional $200 to $500 to a perc test for septic systems.
A soil scientist studies soil’s physical, chemical, and biological properties, typically for agricultural or environmental management. This includes tests such as for soil texture, organic matter content, and nutrient levels, as well as the soil’s ability to absorb water. Soil scientist fees can add an additional $150 to $400 to the cost of percolation testing.
Additional Testing
A traditional perc test involves digging several holes in the soil and filling them with water to measure the absorption rate. This method may be sufficient if the soil in the area is typically shown to be sandy and drain quickly.
A deep hole test is now an additional requirement for many local health departments and involves visually examining the soil layers. This test is conducted to detect staining in the soil and determine the water table’s height. A deep hole test is conducted by an excavator or contractor with an auger and is associated with a higher cost. Additional testing may also come into play after a failed perc test. However, whether or not a second test is required depends on the local jurisdiction’s regulations.
Do I Need a Perc Test?
A perc test is important for determining how suitable soil is for building a septic system or other subsurface structure. The following are some of the reasons a homeowner may need to get a perc test done on their property.
Septic Tank Installation
A septic tank is a large underground tank usually made of concrete, fiberglass, or plastic and buried in the ground. The tank holds wastewater from toilets, sinks, showers, and washing machines and allows it time to separate into layers of solids and liquids. The solids settle to the bottom of the tank, and the liquids are released through a drain field.
A perc test is required prior to the installation of a septic tank system to determine the soil’s ability to absorb liquids. This information is an important aspect of designing a septic system that will work correctly, as the soil’s permeability determines the size of the tank, the absorption field, and the size of the drain lines. A poorly designed system can result in serious health and environmental problems.
Septic System Repair or Replacement
Septic tanks need to be replaced when they are too old, too damaged, or too small to serve the needs of the property. The lifespan of septic tanks depends on the material they’re made from, but if they begin to rust or deteriorate they may become unable to adequately contain waste.
If the tank is too small, it will not be able to hold enough waste and will need to be replaced. Damaged tanks may have cracks or holes, allowing waste to leak out and contaminate the surrounding environment.
HIring one of the best septic tank cleaning services can help prevent the need for repairs. But if the damage is done, percolation tests must be conducted before any repairs are made to an existing septic system in order to determine the most effective repair strategy. Tests are also required before an inadequate septic system is updated, upgraded, or replaced.
Drain Tile Installation
A drain tile is a type of underground drainage system used to collect and remove excess water from around a foundation or basement. It consists of a network of perforated pipes that are buried in the ground and connected to a sump pump. Water is then diverted away from the foundation or basement and away from the home.
A drain tile installation helps prevent a home’s foundation from cracking or shifting due to water pressure. It can also help to prevent mold and mildew accumulation while reducing the amount of water that enters the sewer system, helping to protect the environment and reduce water waste. A perc test is necessary for a drain tile installation to ensure that it’s installed correctly and in soil suitable for proper drainage.
Infiltration Basin Installation
An infiltration basin is a shallow, landscaped depression designed to collect and store stormwater runoff so it can infiltrate the soil. It is usually filled with gravel or rock to provide a porous surface that will allow stormwater to enter the soil. The basin is also planted with vegetation, such as grasses and shrubs, to help slow runoff and reduce erosion.
Like dry wells, infiltration basins reduce the number of pollutants and other contaminants that enter local water sources. A perc test is usually required for an infiltration basin installation to ensure that the basin is installed in a suitable location and can efficiently collect and store runoff water.
Agricultural Purposes
The drain rate of soil is important for agricultural purposes. It helps determine which crops to grow and where to grow them. For example, potatoes require drier, loamier soil than other vegetables and fruits, which require moist soil. This means that potatoes need a higher drain rate than other crops.
Similarly, fruit trees need soil that drains well, since oversaturation removes oxygen and prevents root growth. Although government agencies don’t usually require a perc test for land that’s being used for agricultural purposes, it is still beneficial for farms and homesteads wanting to understand the drain rate of their soil. For small-time gardeners looking to boost their chances of a green garden, choosing one of the best soil test kits is likely the way to go.
Flood Risk Detection
Purchasing a property prone to flooding can be risky. Floods can cause major damage to homes, leading to costly repairs. Homeowners may also suffer financial losses due to increased insurance premiums and decreased property values.
A perc test can be a great way to assess the flood risk of a home or property, even before it’s been purchased. When touring properties, hopeful homeowners can include a contingency in an offer that states a positive percolation test on the described lot must be obtained before a contract can be put into motion. If a perc test detects flood risks, it may be better to pursue a different property.
Perc Tests: DIY vs. Hiring a Professional
For homeowners interested in saving money on a soil drainage test, a DIY approach might make the most sense. Just about anyone can learn the basics of a perc test and perform the steps themselves. But it’s important to know that DIY tests won’t satisfy local requirements.
That’s not to say a DIY approach to a soil percolation test isn’t an option. It can make sense for those looking to purchase a property. If an interested home buyer knows what to look for as far as soil type and water tables, a quick DIY test can tell them if a property is more likely than not to fail a professional perc test after purchase and leave them with a piece of land unsuitable for a septic system and not connected to a municipal sewer.
But without the necessary tools and experience, it’s wise to take the results of a DIY perc test with a grain of salt. Perc tests are typically performed by state-licensed professionals to ensure that they are done correctly. In fact, most of the time perc testing must be completed by professionals certified for the work before a septic system permit will be issued. In other words, a DIY perc test isn’t an option in most scenarios.
A homeowner can rest easy by hiring a professional to complete a perc test and knowing they have the experience, knowledge, and tools to do the job right. Additionally, a professional can provide invaluable advice on how to proceed after the perc test results are in.
How to Save Money on Perc Test Cost
Perc tests are essential for determining the absorption rate of soil and are required for certain types of construction projects, such as the installation or repair of septic systems. While the tests can be expensive, there are ways to save money.
- Research local regulations. It’s always advisable to research any local regulations that may affect the cost of a perc test to ensure you’re not paying for more testing than what is required.
- Shop around. Contact several companies to get quotes for a perc test, asking about any additional fees associated with the test to prevent surprise costs.
- Negotiate. With quotes from several companies, it may be possible to use the information to negotiate a better price.
- Use available equipment. While DIY perc tests may not be an option, offering up machinery already on site (like a backhoe) may reduce costs.
- Know about repairs vs. replacements. In some municipalities, perc tests for repairs to existing septic systems are free of charge.
- Keep up on maintenance for existing equipment. The cost of septic tank pumping is minimal compared to the price of a perc test and the potential cost of a new septic system.
Questions to Ask About Perc Tests
A land perc test is an important step in the process of determining whether a property is suitable for a septic system. Asking the contractor conducting the perc test the right questions can help ensure accurate results and proper installation of the septic system. The following are some examples of what to ask about the services offered and the perc test process.
- What experience do you have in performing percolation tests?
- What type of equipment do you use to perform a perc test?
- How long does a typical perc test take to complete?
- What type of soil sample will you collect for the perc test?
- What results can I expect from a percolation test?
- Are there any potential risks for my property associated with a perc test?
- How much will the percolation test for my property cost?
- What additional services do you offer related to perc tests?
- Have you ever encountered any problems during a perc test?
- Are you familiar with the local regulations related to perc tests?
- Once the test is completed, do you pull the septic-tank permit?
FAQs
A perc test is an important step for any homeowner looking to install a septic tank on their property. Not only does it provide valuable information about the soil composition and drainage capacity of the land, but it also helps to ensure that the septic tank is installed in a safe and effective manner. The following questions and answers will further explain the process for those still wondering what a perc test cost includes and accomplishes.
Q. What time of the year is best for a perc test?
The best time of year to perform a perc test is during the warmest and driest part of the year. This is usually during the summer months when the ground is not saturated with water. However, many towns regulate when testing must take place, often requiring it to be performed during the wetter months to assess the site under the most challenging conditions. A perc test after rain isn’t uncommon, though it is more difficult to plan for.
Q. Do all properties require a perc test?
No, not all properties require a perc test. A perc test is generally required when a property owner is looking to install a septic system. However, if the property is served by a sewage system or there are no plans to install a septic system, a perc test may not be necessary.
Q. How long is a perc test valid for?
The answer depends on who completes the perc test in question. If it’s completed by a septic system company monitored by the health department, a local health department’s improvement permit/construction authorization remains valid for 5 years. A licensed soil scientist’s evaluation does not have an expiration date; it will typically remain the same unless the area evaluated experiences alterations.
Q. How is a perc test done?
A perc test involves digging several holes of varying depths in the ground, either several inches or several feet deep. Each hole is then filled with water, and the time it takes each hole to absorb the water is measured. The average absorption time is then used to calculate the absorption rate.
Q. What type of soil fails a perc test?
Soils that fail perc tests are those that are highly impermeable or that have poor drainage. These soils would include those with a high clay or rock content. Impermeable soils prevent water from moving freely, leading to poor drainage and the potential for standing water. Loamy soils, which are mixtures of sand, silt, and clay, are ideal for wastewater treatment.
Q. How long does it take to do a perc test?
On average, a perc test takes 1 to 2 days to complete. The soil preparation process typically requires more time than the actual testing phase, which usually takes no more than 4 hours. A septic soil test can take longer if the soil is very dense, the water table is high, or the area being tested is quite large, requiring multiple holes and the associated prep time.
Sources: HomeAdvisor, Fixr, Forbes, Costimates