Fixtures, Fixture Fittings, and Faucets
Installation and clearance
Fixtures must be listed, installed level and secure, sealed to the floor or wall, accessible for cleaning and repair, and provided with an approved trap and vent. Key dimensional rules to memorize: a water closet needs about 15 inches from the centerline to a side wall, a 30-inch clear width, and roughly 21 inches of clear space in front. Lavatories, urinals, and showers have their own spacing and privacy requirements, and accessible fixtures must meet reach-range, knee-clearance, and control-operability rules.
Fixtures and fixture fittings
Know the difference between a fixture (water closet, sink, tub) and a fixture fitting (faucet, flush valve, drain assembly, supply stop). Standard water-conservation limits are common exam items: water closets around 1.6 gallons per flush (WaterSense models 1.28), urinals about 1.0 gpf, showerheads about 2.5 gpm at 80 psi, and lavatory/kitchen faucets about 2.2 gpm unless a stricter local standard applies. Flushometer valves need adequate pressure and a vacuum breaker; fill valves must be anti-siphon; faucets must be lead-free.
Traps in questions
Watch for fixtures installed without access for service, a hose bibb without a vacuum breaker, a below-rim supply on a sink without an air gap, and shower valves without anti-scald protection. Also watch for a fixture installed at a lower elevation than the drain it discharges into without a lift pump.
Worked example
A vanity wall is 60 inches long. Two lavatories need spacing that keeps each basin clear of the other and of the side walls; plan the rough-in around the fixture's listed rough-in dimensions rather than centering blindly, and confirm the drain and supply locations before the wall is closed.