13.3 Water Service Details, Treatment Units, Softeners, & Residential Sprinklers (UPC 604, 609, 611, 612; WA Amendments)

Building Supply Materials and Location

• 604.10 Plastic building supply: Approved plastic may be used for the building supply. Where a metal building supply is used for electrical grounding, replacement piping must be of like material.
• 604.10.1 Tracer wire: Plastic building supply piping installed outside and underground needs a blue insulated copper tracer wire or other approved conductor laid next to it. The wire is at least 18 AWG, has insulation rated for direct burial, and is either accessible or ends aboveground at each end of the nonmetallic pipe.
• 609.1 Depth: Yard piping goes at least 12 inches below the average local frost depth, with at least 12 inches of cover.
• 609.2 Common trench with sewer: The water pipe must be at least 12 inches above the sewer and on a shelf at least 12 inches to the side (Section 4.1).
• 609.6 and 609.7 Location: A building supply may not be located on a lot other than the one it serves. Exception: an abutting lot may be used to reach an available public water service where proper cause and a legal easement are established to the AHJ's satisfaction.

Washington 604.14: Plastic water service termination

Plastic water service piping may terminate within a building, provided the connection to the potable water distribution system is made as near as practical to the point of entry and is accessible. Barbed insert fittings with hose clamps are prohibited as a transition fitting within the building.

In practice, a PE water service entering a crawl space or garage transitions to the building's distribution piping close to the wall, at an accessible location, using a listed transition fitting rather than a barbed insert and hose clamp.

Drinking Water Treatment Units (UPC 611)

Table 611.4, residential water softeners:

A kitchen sink and dishwasher, a laundry tray, and an automatic clothes washer are permitted without increasing the size. Over four bathroom groups, the softener is engineered for the installation.

Remember 610.2: a softener's or filter's pressure loss must be included when sizing the water system (Section 12.3).

Residential Fire Sprinklers (UPC 612 as Amended)

The unamended 2015 UPC 612 describes multipurpose and stand-alone residential sprinkler systems as an equivalent to NFPA 13D. Examples include sprinkler temperature ratings of 135 to 170°F, installation by ASSE Series 7000 certified installers, and design details. Washington replaces it:

612.1 General. Where residential fire sprinkler systems are installed, they shall be installed in accordance with the International Building Code or International Residential Code. Sections 612.2 through 612.7.2 are not adopted.

Two related Washington rules:

• Backflow for fire systems (603.5.14 as amended): A potable supply to a fire system normally under pressure needs a DC, DC detector, RP, or RP detector. The exception covers one- and two-family or townhouse flow-through or combination systems piped in potable-approved materials. Systems with antifreeze or chemicals need an RP or RP detector.
• WAC 246-290-490: Backflow protection is not required for residential flow-through or combination systems built of potable materials. Other fire systems follow the UPC.

A flow-through system connects sprinkler piping in series with plumbing fixtures, so water moves through the sprinkler piping whenever a fixture is used. That keeps the water from stagnating, which is why the exception exists.

Potable Water Tanks and Pumps (Cross-Reference)

• 607: tanks meet NSF 61, are covered and vented with No. 24 mesh, have an overflow of at least 16 square inches, and have relief and vacuum relief valves as required (Section 4.3).
• 609.8: booster pumps need a low-pressure cutoff at 10 psi, within 5 feet of the inlet (Section 4.3).

Scenario: Replacing a Water Service at a House

1. If the old galvanized service is used for electrical grounding, 604.10 requires the replacement to be of like (metal) material. Where it is not used for grounding, an approved plastic such as PE may be used. This scenario assumes PE is allowed.
2. Lay a blue insulated 18 AWG copper tracer wire with the PE, accessible or ending aboveground at each end.
3. Bury the pipe at least 12 inches below frost depth, with 12 inches of cover, and separate it from the sewer per 609.2.
4. Inside the building, transition near the point of entry at an accessible location, without barbed insert fittings and hose clamps (Washington 604.14).
5. Put a fullway valve on the discharge side of the meter (606.2).
6. If a softener is added for three bathroom groups, give it a 1-inch connection (Table 611.4), and count its pressure loss when checking the system.