7.2 Water-Conserving Fixtures, Faucets & Fixture Supply Connectors
Key Takeaways
Lavatory faucets are limited to 2.2 gpm at 60 psig, and metering lavatory faucets to 0.25 gallon per cycle at 80 psig.
Showerheads are limited to 2.5 gpm and dwelling-unit kitchen sink faucets to 2.2 gpm, both at 80 psig.
Water closets and their flushing devices are limited to 1.6 gallons per flush; urinals and urinal flushing devices to 1 gallon per flush.
Water closets must work across static test pressures of 20 to 80 psig for tank types, 25 to 80 psig for siphonic flushometer types and 35 to 80 psig for blowout flushometer types.
Flexible fixture supply connectors must meet ASME A112.18.6, be installed only where accessible, and be marked for accessible locations.
Which fixtures are covered (SPS 384.20 (3) (a))
All lavatory faucets, showerheads, urinals, urinal flushing devices, water closets and water closet flushing devices must meet the limits in par. (b). Kitchen sink faucets in dwelling units and living units must meet the sink-faucet limit. Flow controls or restrictors must be on the inlet side or built into the faucet, spout or fixture. A flow-restricting aerator counts as an integral part of the faucet.
Maximum flow and flush volumes (SPS 384.20 (3) (b))
| Fixture or device | Maximum | Test condition |
|---|---|---|
| Lavatory faucet | 2.2 gpm | 60 psig flowing |
| Metering lavatory faucet | 0.25 gallon per cycle | 80 psig flowing |
| Showerhead | 2.5 gpm | 80 psig flowing |
| Sink faucet | 2.2 gpm | 80 psig flowing |
| Urinal | 1.0 gallon per flush | 80 psig flowing |
| Urinal flushing device | 1.0 gallon per flush per use | Static 20 and 80 psig |
| Water closet | 1.6 gallons per flush | Over the Table 384.20 range |
| Water closet flushing device | 1.6 gallons per flush | Over the Table 384.20 range |
Notice the lavatory test pressure is 60 psig, while the showerhead, sink and urinal tests are at 80 psig.
Table 384.20: static test pressures for water closets
| Water closet type | Must function from |
|---|---|
| Tank type | 20 to 80 psig |
| Flushometer, siphonic | 25 to 80 psig |
| Flushometer, blowout | 35 to 80 psig |
These ranges are product test ranges. The minimum flow pressure you design for at the fixture supply comes from SPS 382.40 (7) (d), section 5.2: 15 psig for siphonic flushometer and washdown closets, 20 psig for one-piece tank closets, 25 psig for blowout fixtures, and 8 psig or the manufacturer's minimum for other fixtures such as two-piece tank closets.
How the limits interact with other rules
- Shower trap exception. SPS 382.32 (3) (e) 2. allows a 1-1/2 inch trap for a shower replacing a residential tub only if the showerhead flows 2.5 gpm or less, with one control valve and no simultaneous heads (section 4.1).
- Supply sizing. Pipe sizing still uses the wsfu values in Tables 382.40-1b and 382.40-2. Using a lower demand for low-flow fixtures requires an approved alternate method, such as the IAPMO Peak Water Demand Calculator under SPS 381.20 (2), or an engineering analysis.
- Hot water delivery. A low-flow lavatory takes longer to deliver hot water, which is why public lavatories have the 8-ounce or Table 382.40-1d length limits (section 5.4).
Faucets, showerheads and connectors (SPS 384.20 (6))
| Item | Standard and conditions |
|---|---|
| Faucets and showerheads | ASME A112.18.1/CSA B125.1 |
| Flexible fixture supply connectors | ASME A112.18.6/CSA B125.6; only in accessible locations; marked with the manufacturer and "For use with water in accessible locations only"; cold-only connectors marked "Only for use with cold water" (marking exemptions apply to connectors integral to a compliant faucet) |
| Hand-held showers and fittings with integral hose outlets | ASME A112.18.1/CSA B125.1, or fitted with an ASME A112.18.3 backflow device |
Connector length limits are in SPS 382.40 (7) (h): 24 inches upstream of a fixture or faucet body and 10 feet upstream of an appliance (section 5.2). A hand-held shower is limited to 5 feet of backpressure under SPS 382.41 (4) (f).
Backflow protection built into fixtures
- Flushometer valves: ASSE 1001 vacuum breakers.
- Tank fill valves: anti-siphon, ASSE 1002, critical level at least 1 inch above the overflow.
- Bidets with submerged inlets: ASSE 1001 or CSA B64.1.1 vacuum breakers.
- Clothes washers, clothes dryers and residential dishwashers: integral air gap or a Table 382.41-1 device.
- Commercial dishwashers: ASSE 1004. Residential food waste grinders: ASSE 1008.
Worked examples
- A replacement lavatory faucet is rated 1.5 gpm at 60 psi, so it complies (limit 2.2).
- A "rain" showerhead is rated 3.0 gpm at 80 psi, so it does not comply (limit 2.5), and it would also void the 1-1/2 inch tub-to-shower trap exception.
- A dual-flush closet rated 1.6/1.1 gallons: the full flush is at the 1.6 gallon limit, so it complies.
- A metering faucet in a public restroom delivers 0.35 gallon per cycle at 80 psi, so it fails the 0.25-gallon limit.
Exam traps
- Using the 1.28-gpf WaterSense "high-efficiency" figure; the Wisconsin code limit is 1.6 gallons per flush.
- Mixing the 60 psig lavatory test pressure with the 80 psig showerhead test pressure.
- Forgetting that the dwelling-unit kitchen sink faucet limit (2.2 gpm) applies to every dwelling and living unit.
What maximum discharge rate does SPS 384.20 (3) (b) set for a showerhead?
2.2 gpm at 60 psig
1.5 gpm at 80 psig
2.5 gpm at 80 psig
3.0 gpm at 80 psig
Across what static pressure range must a blowout-type flushometer water closet function under Table 384.20?
35 to 80 psig
20 to 80 psig
25 to 80 psig
15 to 60 psig
What is the maximum flush volume for a water closet installed in Wisconsin under SPS 384.20 (3) (b) 7.?
1.28 gallons
1.6 gallons
2.0 gallons
3.5 gallons
Sections you finish are checked off in the contents.