A septic system — the tank is only half of it

The tank is only half the system: solids settle and digest in the tank, then liquid disperses through the drainfield — sized separately by a perc test.

Cross-section of a septic system from house to soil. Waste flows to the septic tank, where solids settle as sludge on the bottom, grease floats as a scum layer on top, and clarified liquid in the middle passes an outlet baffle to the drainfield. In the drainfield, perforated pipe in gravel trenches disperses the effluent into the soil. The tank is sized by bedroom count; the drainfield is sized separately by a percolation test. — Source: State septic code + EPA onsite wastewater

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Cross-section of a septic system from house to soil. Waste flows to the septic tank, where solids settle as sludge on the bottom, grease floats as a scum layer on top, and clarified liquid in the middle passes an outlet baffle to the drainfield. In the drainfield, perforated pipe in gravel trenches disperses the effluent into the soil. The tank is sized by bedroom count; the drainfield is sized separately by a percolation test.

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    Diagram: <a href="https://remodelcalculators.com/construction-diagrams/septic-tank-drainfield" target="_blank" rel="noopener">A septic system — the tank is only half of it</a> — courtesy of <a href="https://remodelcalculators.com" target="_blank" rel="noopener">RemodelCalculators.com</a>
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Septic Tank Size Calculator

Free septic tank size calculator — minimum tank capacity by state and bedroom count from state code, with garbage-disposal adders and formula-state rules.

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