1. (a) The department shall classify a PWS as a community water system (CWS) if:

   1. (1) The dwellings, units, or other structures served by the system are suitable for year-round occupancy;
   2. (2) The calculation of the number of year-round residents does not include weekend, seasonal, or other transient or temporary occupants; and
   3. (3) Based on (1) and (2) above, the definition of community water system in RSA 485:1-a, I, is met.

2. (b) For purposes of (a)(1) above, a dwelling, unit, or other structure shall be considered suitable for year-round occupancy if it:

   1. (1) Has insulation, a heating system, a year-round potable water supply, and indoor plumbing; and
   2. (2) Is served by a wastewater disposal system that does not discharge untreated waste directly to surface waters and an alternating current electric power supply.
3. (c) The department shall classify a PWS as a CWS if the PWS will ultimately serve a permanent year-round residential population, even if it initially serves only weekend, seasonal, or other transient or temporary occupants.

4. (d) Subject to (e), below, the department shall determine the population being served by:

   1. (1) For units with 2 or more bedrooms, using an occupancy of 2.5 people per unit;
   2. (2) For units with less than 2 bedrooms, such as efficiency apartments, elderly housing units, or other similar types of residences, using an occupancy of 1.5 people per unit; or
   3. (3) Analyzing an overlay of water system distribution lines with the most recent U.S. government census estimate using geographic information system data.
5. (e) If the PWS owner has existing customer records that show a different population than is calculated pursuant to (d) above, the owner may submit the data to the department for purposes of the department’s calculations.

Source. (See Revision Note at part heading for Env-Dw 401) #10608, eff 6-1-14; ss by #14158, eff 12-25-24 (formerly Env-Dw 401.01)