Free Web Tool · DENR DAO 2019-19

Septic Tank Sizing

Three-compartment septic tank sizing for a residence or small establishment — wastewater volume, sludge accumulation, and recommended dimensions per Philippine standards.

Input

Results

Daily wastewater Q (L/day)
Liquid retention volume Vl (m³)
Sludge volume Vs (m³)
Total volume Vt (m³)
Plan area A (m²)
Recommended W × L (m)
Compartments
Method

Q = persons · wwPC. Liquid retention V_l = Q · retention/24 (L). Sludge V_s = persons · sludge_pPyr · desludge (L). Total V_t = (V_l + V_s)/1000 (m³). A = V_t / depth. W = √(A / (L/W)). 3 compartments typical for ≤ 30 persons.