Blueprint: Greywater Treatment and Reuse Bed — Build Specification

Design blueprint — simulated, not measured — not built, not load-tested. Build specification for a household gravel-and-reed subsurface-flow greywater bed (6.5 m2, 0.60 m deep, 5.93 days retention for 250 litres per day; computed effluent BOD 41.1 to 6.7 mg/L across 10 to 30 C; subsurface irrigation only; clogging horizon 3.52 years without a pre-filter and 7.05 years with one), derived from the source paper DOI 10.5281/zenodo.24109197. Performance is computed, not measured; local health rules govern use. The source paper gives no prices, so the blueprint lists quantities without prices.