WAC 246-335-748. Plumbing

An applicant must design and install plumbing, including: (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) Trap primers in floor drains and stand pipes subject to infrequent use; (3) Wrist, knee or foot faucet controls or equivalent and gooseneck spouts on handwash sinks; (4) Insulation on: (a) Hot water piping systems; (b) Cold water and drainage piping; and (c) Piping exposed to outside temperatures. (5) Equipment to deliver hot water at point of use as follows: (a) 120°F or less for handwash sinks and bathing fixtures; (b) 160°F or more for laundry washers; (c) 120°F or more for laundry washers using chemical sanitation.