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 372 - DESIGN STANDARDS FOR SMALL COMMUNITY WATER SYSTEMS
Section Env-Ws 372.10 - Design Flow

Universal Citation: NH Admin Rules Env-Ws 372.10

Current through Register No. 13, March 27, 2025

(a) Subject to (b), below, anticipated design flows for a proposed small communitywater system shall be based on the type of use, as specified in Table 372-1below:

Table 372-1

Anticipated Design Flows

Type of Use Design Flow
Single family homes 150 gpdper bedroom
Recreational/vacation homes 150 gpdper bedroom
Mobile homes 150 gpdper bedroom
Apartments/Condominiums 150 gpdper bedroom
Efficiency Apartments 225 gpd per unit
Elderly Housing:
One bedroom 150 gpdper unit
2 or more bedrooms 100 gpdper bedroom
Nursing Homes 125 gpdper bed
Dormitories 100 gpdper student
Other Institutions 135 gpdper bed

(b) If the specific type of use is not listed above, the design flow shall be determined in accordance with Env-Ws 1008.

(c) For small community water systems that are being expanded or upgraded, the design flow shall be determined either in accordance with (a) and (b), above, or by using historical water readings in accordance with one of the following:

(1) By finding the daily average flow from water meter readings and multiplying the average by a minimum factor of 2 or a maximum factor of 3 depending on the type or frequency of the meter readings; or

(2) By examining 12 months of consecutive daily water meter readings, in which case the water system's design flow shall be based on the highest daily flow noted, without application of a multiplying factor.

(d) Since design flows contained in Table 372-1 and Env-Ws 1008 do not include exterior water use, for those water systems where watering lawns and garden, filling swimming pools, supplying fire protection systems such as hydrants or sprinklers, and other unusually high water demand situations are expected, additional supply capacity shall be provided.

(See Revision Note at chapter heading Env-Ws 300) #6521, eff 6-4-97; ss by #8360, INTERIM, eff 6-4-05, EXPIRES: 12-1-05; ss by #8496, eff 11-30-05

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