In a septic system, the larger solids and grease are removed from the wastewater by the septic tank. However, the effluent that exits the tank still contains various pollutants that need to be eliminated before the water can be safely discharged into surface or groundwater sources. Specifically, the septic tank effluent may harbor harmful microorganisms that can cause illness in humans, while the organic matter present in the effluent can produce unpleasant smells. Additionally, the nitrogen and phosphorus nutrients in the wastewater may have detrimental effects on aquatic organisms. Thankfully, deep, permeable and unsaturated soil has the ability to naturally filter out these contaminants.
Soil is a key component to creating a healthy, viable, correctly installed septic system. Without the right soil, it’s likely your system will require frequent maintenance— and may even require relocation and replacement.
A soil evaluation for home septic systems is one of the most important parts of Acuantia’s septic system services. It is crucial to conduct a soil test before installing a septic system, as certain soil types like black soil, sand, and rock can pose significant harm to the system. Black soil has the tendency to expand and contract, leading to instability and pressure problems for the septic system. This instability can potentially cause damage and compromise the overall functioning of the system. Sand, on the other hand, can quickly clog the septic system, hindering the proper flow of wastewater and leading to blockages and backups. Furthermore, rocks present a long-term threat to septic systems, gradually causing damage and deterioration over time. To ensure a successful septic system installation near you and prevent costly repairs or replacements, it is essential to perform a soil test to assess the compatibility of the soil with the system and make informed decisions based on the results.
On This Page:
Many homeowners wonder what kind of septic system is best for them. However, the soil type on which the septic system is installed plays just as important a role in its proper functioning, as the septic tank itself. Therefore, choosing the right soil type is crucial for the effectiveness and longevity of the septic system.
The best soil for septic systems has good percolation and drainage properties. Percolation refers to the ability of soil to absorb and filter wastewater, while drainage refers to the ability of the soil to move water away from the septic system. Sandy loam soil is considered the best type of soil for septic systems due to its ability to percolate and drain water quickly.
On the other hand, clay soils are not ideal for septic systems because they have poor drainage and percolation properties. These soils tend to retain water, which can lead to the formation of a soggy and wet drainfield, causing the system to fail. Therefore, it is recommended to avoid installing septic systems in areas with high clay soil content.
You can amend the soil in your septic system site by combining sandy, loamy substrate with your clay soil to improve the percolation properties of the soil for your drainfield. Other factors that can affect the soil suitability for septic systems include slope, vegetation cover, and soil compaction. Slopes greater than 20% can cause wastewater to move too quickly through the soil, while dense vegetation can clog the soil pores and affect the percolation process. Soil compaction can also reduce the ability of the soil to absorb and filter water.
In addition to soil type, the depth of the soil above the groundwater table is also important. The soil layer between the bottom of the drainfield and the groundwater table should be at least two feet deep. If the groundwater table is too high, the wastewater may not be able to percolate through the soil, leading to saturation of the drainfield and system failure.
Soil permeability is also an essential factor to consider when designing and installing septic systems. Permeability is the ability of the soil to absorb and “leach” or disperse water. In a septic system, waste from a home or building flows into a septic tank where the solids settle and the liquid (or effluent) is discharged into the drainfield or leach field. If the soil is considered permeable, it will absorb and disperse the wastewater fairly quickly, which helps to prevent the buildup of harmful pathogens and contaminants in the soil. However, if the soil is not permeable enough, the wastewater will back up and create a “pool” of wastewater, which would then lead to the failure of the septic system and then contamination of groundwater. Soil type can impact the kind of septic system that can be installed. Highly permeable soil may allow for septic system installation near you with a shallow drainfield, while less permeable soil may require the use of an alternative type of septic systems, like a mound or drip irrigation system.
Soil analysis for septic system design is the process of evaluating the soil’s ability to support your septic system. This type of analysis involves determining the soil type, structure, texture (permeability), and other properties that might affect the absorption and drainage capacity of the soil. Soil analysis is conducted by a soil scientist or a licensed engineer as part of the septic system design & engineering process. The soil analysis helps to determine the appropriate type and size of septic system that can be installed on the site and also helps to determine the location and depth of the septic system’s drain field. The analysis includes taking soil samples from various locations on the property, testing the samples in a laboratory, and analyzing the results to determine their physical and chemical properties. The results from this type of analysis are used to place and design the septic system and to ensure that it is installed in a location that is suitable for the soil conditions on the property.
No, a perc test and a soil test are not the same things, although they can be related. A perc test, short for “percolation test,” is a test that is used to determine how quickly water can drain through the soil in a specific area. It is used to assess whether or not the soil in a particular location is right for the installation of a septic system. During a perc test, a hole is dug in the ground and water is poured into the hole. The engineer will measure the rate at which the water drains away into the soil and this is used to determine whether or not the soil in that spot is suitable for a septic system. A soil analysis is performed to assess the nutrients, pH levels, and other attributes of the soil in a particular location. This data is utilized to identify the suitable plant species that can thrive in the soil and to determine the fertilizers or soil modifications that may be required to enhance the quality of the soil. While perc tests and soil tests are different, they can be related in that the results of a soil test may impact the results of a perc test. For example, if the soil is found to be highly compacted or has a high clay content, it may not be suitable for a septic system, even if it passes the perc test. Similarly, if the soil is found to be highly acidic, it may require lime or other amendments to improve its suitability for plants, even if it appears to be fertile based on a visual inspection.
In general, performing your own perc test or soil test for a septic system is not recommended. These tests require specialized knowledge and equipment and mistakes in the testing process can result in inaccurate results that can lead to a poorly designed or failed septic system. In most areas, perc tests and soil tests for septic systems are required by local code and must be performed by a licensed scientist, engineer or septic system designer. These experts have the training necessary to perform the tests correctly, interpret the results accurately and design a septic system that is appropriate for the site. It is important to work with a licensed professional who can guide you through the process to ensure that the system is designed and installed correctly.
The cost for a perc test, depending upon your area and your state and/or county requirements, can range from $750 to $1800. The cost for a soil test is separate and can range from $600 to $7,500, also dependent upon the state or local regulations and requirements.
The significant difference in the price range for soil evaluations across different regions in the country can be attributed to several factors. Firstly, variations in the cost of living and labor expenses play a role. States like California generally have higher living costs and wages, which can contribute to the higher price tags associated with soil evaluations. Conversely, states like Texas may have lower living costs and more competitive labor markets, resulting in comparatively lower prices for these evaluations. Additionally, local regulations and requirements can impact the complexity and extent of the evaluation process, influencing the pricing accordingly. In the case of Wisconsin, where soil evaluations are not typically included in the design, the separate cost may reflect the specialized expertise required and the additional steps involved in assessing the soil suitability for a septic system. These factors contribute to the significant gap in the price range for soil evaluations for home septic systems across different regions of the country.
We solve homeowners’ onsite wastewater needs by: