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Septic Tank
BUILDING MATERIALS & CONSTRUCTIONintermediate
Definition
Septic tank or wastewater treatment system — an underground chamber where household wastewater is treated through bacterial decomposition before percolation to soil. Septic tanks are sized based on occupancy (typically 3.5–5 m³ for a four-person household) and must be desludged every 2–3 years. They are the standard wastewater treatment system in Indonesian areas without central sewage.
Example
An Indonesian suburban house has a 4 m³ concrete septic tank buried 2 metres underground — receiving waste from the kloset and wastafel, with an outlet pipe discharging treated effluent to a percolation pit (sumur resapan) beneath the garden.