New Hampshire Code of Administrative Rules
Env - Department of Environmental Services
Subtitle Env-Ws - Division of Water
Chapter Env-Ws 300 - NEW HAMPSHIRE DRINKING WATER RULES
Part Env-Ws 380 - FILTRATION, DISINFECTION, TREATMENT PLANT AND WASTE RECYCLING
Section Env-Ws 380.11 - Disinfection Requirements for Systems Providing Filtration
Current through Register No. 13, March 27, 2025
Each owner of a public water system that provides filtration treatment shall provide disinfection treatment as follows:
(a) The disinfection treatment shall be sufficient to ensure that the total treatment processes of that system achieve at least 99.9 percent inactivation or removal of giardia lamblia cysts , or both, and at least 99.99 percent inactivation and removal of viruses;
(b) The residual disinfectant concentration in the water entering the distribution system shall not be less than 0.2 mg/l for more than 4 hours;
(c) The residual disinfectant concentration shall be as follows:
V = c + d + e/a + b x 100
#5098, eff 3-18-91, EXPIRED 3-18-97
New. #6521, eff 6-4-97 (See Revision Note at chapter heading for Env-Ws 300); ss by #8352, eff 5-14-05 (formerly part of Env-Ws 380.15 )