New Hampshire Code of Administrative Rules
Env - Department of Environmental Services
Subtitle Env-Dw - Drinking Water Programs
Chapter Env-Dw 400 - PUBLIC WATER SYSTEM CLASSIFICATION AND DESIGN
Part Env-Dw 405 - DESIGN STANDARDS FOR SMALL COMMUNITY WATER SYSTEMS
Section Env-Dw 405.10 - Design Flow
Current through Register No. 13, March 27, 2025
(a) Subject to (b), below, anticipated design flows for a proposed small community water system shall be based on the type of use, as specified in Table 405-1 below:
Table 405-1: Anticipated Design Flows
| Type of Use | Design Flow |
| Single family homes | 150 gpd per bedroom |
| Recreational/vacation homes | 150 gpd per bedroom |
| Mobile homes | 150 gpd per bedroom |
| Apartments/Condominiums | 150 gpd per bedroom |
| Efficiency Apartments | 225 gpd per unit |
| Elderly Housing: | |
| One bedroom | 150 gpd per unit |
| 2 or more bedrooms | 100 gpd per bedroom |
| Nursing Homes | 125 gpd per bed |
| Dormitories | 100 gpd per student |
| Other Institutions | 135 gpd per bed |
(b) If the specific type of use is not listed above, the design flow shall be determined in accordance with Env-Wq 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:
(d) Since design flows contained in Table 405-1 and Env-Wq 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 part heading for Env-Dw 405) #10612, eff 6-1-14
