Water Supply

Chlorine Dose

Mass of chlorine — and equivalent bleaching powder — required per day for disinfection.

Formula
Mass = Q · Dose,  Bleaching powder = Mass / (% available Cl)

Typical residual at consumer end: 0.2–0.5 mg/L; applied dose: 1–3 mg/L plus chlorine demand.

Fresh bleaching powder (CaOCl₂) ≈ 30–35%; high-test calcium hypochlorite (HTH) ≈ 65–70%.

Resultlive
Pure chlorine required
3kg/day
Bleaching powder required
10kg/day
Stock solution (5%) volume
200L/day
Per month (≈ 30 days)
300kg
Stock solution (5%) volume: If feeding chlorine as a 5%-by-mass stock solution.
Per month (≈ 30 days): Bleaching powder consumption.
Reference: Mass balance for chlorination. Stock-solution volume assumes 5% w/w (50 g/L) preparation.