Indicator

Value range

Fecal coliforms (Most probable number, MPN/L)

≤900

Enteric pathogens

Not detected

Mycobacterium tuberculosis

Not detected

Disinfection contact time

≥1.5 h (Chlorination)

≥0.5 h (Chlorine dioxide method)

Total residual chlorine (mg/L)

≥6.5 (Chlorination)

≥4.0 (Chlorine dioxide method)