Good and Bad Soils for the Septic System

No matter what kind of septic system you have you can count on one thing: it relies on soil to complete the process of transporting wastewater from your home. The soil beneath your drainfield is the key to filtering all the effluent coming from the septic tank. The composition of your soil is the key to its effectiveness. Here we review different types of soil and how they impact your septic system.

What’s in Soil?

Any random sample of soil reveals the basic breakdown. Soil is composed of 50% solid material and 50% pore space. Within the solid material you can find organic plant matter, and three mineral types: sand, clay, and silt. Within the pore space you find space that is filled with both water (25%) and air (25%). The texture of soil is what mainly influences the effectiveness of the soil for filtering wastewater.

Soil texture varies by the proportions of the different sized mineral particles. Sand particles are the biggest of them all, as they are visible to the naked eye and have a gritty texture. They range from 0.05-2.0 mm in diameter compared to silt particles (0.002-0.05 mm) that feel like flour and require a microscope. Clay particles are the smallest at >0.002 mm and they become sticky when wet. The texture determines how quickly the effluent will be absorbed by the drainfield, which is why properly balanced soils work best.

Is My Soil Good or Bad?

Good drainfield soil can be difficult to assess without a professional. There are different properties of soil to consider during a soil assessment, including texture, structure, density, and color. In general, you want sandy soil that is not too coarse, well-drained soil, and naturally undisturbed soils to absorb the effluent. When the soil is too coarse, wastewater passes too quickly to receive sufficient treatment. Soil that has a high clay content is also undesirable as clay holds water for too long causing it to drain too slowly. Clay particles can also swell and block soil passages slowing down the effluent’s movement even further. When the passage of wastewater is completely blocked, drainfield failure follows. This condition is known as hardpan.

Help your wastewater receive the care it needs by adding good bacteria back into the septic system with a monthly additive like Septic Maxx. You can use this natural product once a month to boost the good bacteria content. Try a free trial by calling 800-397-2384.

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