10.1 Alternate Water Sources: Reclaimed, Gray, and On-Site Treated Water (UPC Chapter 15 as Amended by Washington)

Scope

L&I lists UPC Chapter 15 in the Part 1 content. The chapter covers alternate water sources for nonpotable applications:

• Reclaimed (recycled) water: treated wastewater delivered by a utility (1503).
• Gray water: untreated wastewater from bathtubs, showers, lavatories, and clothes washers (1502).
• On-site treated nonpotable water: gray water or other water treated on site for uses such as flushing (1504).

Rainwater catchment is in Chapter 16 (Section 10.2).

Washington Amendments to Chapter 15

Exam trap: Questions built on UPC 1502 gray water details (surge tanks, mulch basins, emitters, irrigation field sizing) describe provisions that Washington does not adopt. In Washington, gray water irrigation falls under Department of Health rules.

General Requirements Still in Effect (UPC 1501)

• 1501.3 Permit: A permit is required to build, install, or alter an alternate water source system.
• 1501.5 Maintenance: Inspect and maintain per Table 1501.5 and the manufacturer. The property owner keeps a maintenance log for permitted systems. The designer supplies an operation and maintenance manual.
• 1501.9: No mercury-containing controls may contact alternate water.
• 1501.10 Signs: Restrooms in commercial, industrial, and institutional buildings that flush with reclaimed or on-site treated water get signs with 1/2-inch letters. Equipment rooms get signs with 1-inch letters.
• 1501.12 Separation: Treated nonpotable pipes may share a trench with potable pipes at 12 inches minimum vertical and horizontal separation when both materials are approved for use within a building.
• 1501.14 Sizing: Size alternate water piping per Chapter 6, like potable piping.

Identification (UPC 601.3)

Reclaimed water valves, except fixture supply controls, have locking features (1503.8). Hose bibbs on reclaimed systems are not allowed in areas accessible to the public. Public access uses a quick-disconnect different from potable, and bibbs are labeled (1503.9). Reclaimed pipes may share a potable trench at 12 inches vertical and horizontal separation; otherwise the horizontal separation increases to 60 inches, and potable is always above reclaimed (1503.11).

Cross-Connection Inspection and Testing (UPC 1501.11)

1. Supply test (1501.11.1): Test alternate water piping like potable piping (Section 1.2).
2. Initial and annual inspection and test (1501.11.2): Isolate potable and alternate systems and test each independently. A visual inspection checks meters, pumps, signs, exposed piping, and valve lock seals. Cross-connection testing is required annually by the AHJ unless site conditions do not require it, but never less than once every 4 years.
3. Cross-connection test (1501.11.2.2):
   • Pressurize the potable system. Shut down, depressurize, and drain the alternate system.
   • Keep the alternate system empty for the time the AHJ sets, never less than 1 hour.
   • Check the alternate system's drain and all outlets. Flow from an alternate outlet indicates a cross-connection. No flow from a potable outlet means it is connected to the alternate system.
   • Then reverse the procedure: depressurize the potable system and test the other way.
4. Discovery of a cross-connection (Washington 1501.11.2.3):
   1. Shut down the reclaimed water piping at the meter and drain the riser.
   2. Shut down the potable water at the meter.
   3. Uncover and disconnect the cross-connection.
   4. Retest the building.
   5. Chlorinate the potable system at 50 ppm for 24 hours.
   6. Flush, then have a bacteriological test performed by a laboratory certified for drinking water in Washington. Recharge only when the AHJ, the health authority, and the purveyor accept the results.