An applicant must design and install plumbing, including:

1. (1) Backflow prevention. Devices on plumbing fixtures, equipment, facilities, buildings, premises, or areas which may cause actual or potential cross-connections of systems in order to prevent the backflow of water or other liquids, gases, mixtures, or substances into a water distribution system or other fixtures, equipment, facilities, buildings, or areas;
2. (2) Trap primers in floor drains and stand pipes subject to infrequent use;
3. (3) Wrist, knee or foot faucet controls or equivalent and gooseneck spouts on handwash sinks;

4. (4) Insulation on:

   1. (a) Hot water piping systems;
   2. (b) Cold water and drainage piping; and
   3. (c) Piping exposed to outside temperatures.

5. (5) Equipment to deliver hot water at point of use as follows:

   1. (a) 120°F or less for handwash sinks and bathing fixtures;
   2. (b) 160°F or more for laundry washers;
   3. (c) 120°F or more for laundry washers using chemical sanitation.

[Statutory Authority: RCW 70.127.120 and 43.70.250. WSR 18-06-093, § 246-335-748, filed 3/6/18, effective 4/6/18.]