Plumbing Fixtures, Faucets, and Appliances
Fixture questions mix code clearances, listed standards, water-conservation limits and accessibility. The exam expects you to place a fixture correctly, choose a compliant model, and connect it with a proper trap and waste.
Clearances and fixture counts
- Water closet: 15 inches from centerline to any side wall or partition, 30 inches minimum clear width, and 21 inches clear in front (24 inches where a local amendment says so).
- Lavatories and similar fixtures: 4 inches minimum from a side wall to the fixture edge.
- Fixture counts come from the occupancy tables - the number of water closets, lavatories and drinking fountains is set by occupant load and sex, not by owner preference.
Conservation and listing limits
California limits: toilets 1.28 gpf, urinals 0.5 gpf (0.125 gpf in much new construction), showerheads 2.0 gpm at 80 psi, residential kitchen faucets 1.8 gpm, lavatory faucets 1.5 gpm, public lavatory faucets 0.5 gpm. Each fixture carries a listed mark - ASME A112.19.2/CSA B45.1 for china, ASME A112.18.1/CSA B125.1 for faucets.
Traps and connections
Every fixture without an integral trap gets a properly sized trap with a 2 to 4 inch seal. Dishwashers need an air gap or listed air-break; clothes washer standpipes run 18 to 30 inches above the trap; drinking fountains and bottle fillers need lead-free waterways and accessible spout heights.
Accessibility
CBC Chapter 11B governs: 17 to 19 inch seat height, grab bars at 33 to 36 inches, 60 inch turning circles, and knee clearance beneath lavatories.
Worked example
A restaurant wants three water closets in a row along one wall. Space required = 15 in end clearance + (30 x 3) + 15 in = 120 in, or 10 ft. If the available wall is 9 ft, only two fit; the third moves to the opposite wall, and each still needs 21 inches of clear frontage.
Traps
- Setting a water closet closer than 15 inches to a wall.
- Adding a bar or prep sink without recalculating fixture units.
- Omitting escutcheons, trap primers, or the dishwasher air gap.
- Assuming ADA clearances automatically satisfy CPC spacing - they are separate tests.