Fixtures, Faucets, and Appliances: Ratings, Water Use, and Access
The fixture is a rated device
Every fixture has a fixture-unit value, a required trap size, and a maximum water use. Know the federal and code figures: water closets at 1.6 gpf maximum (1.28 gpf for most current models), urinals around 1.0 gpf (0.5 or less for high-efficiency), lavatory and kitchen faucets at 2.2 gpm at 60 psi, showerheads at 2.5 gpm at 80 psi, and public lavatory faucets at 0.5 gpm. Replacing a fixture means meeting current standards, not the standard in place at construction.
Installation requirements
Fixtures must be approved, securely fastened, level, sealed to the finished surface, accessible for cleaning and repair, and trapped separately except where code permits a combination. Floor drains in public and commercial toilet rooms require trap seal primers or an approved equivalent. Hose bibbs, sillcocks, and any threaded outlet that can accept a hose need backflow protection. Appliances - dishwashers, washing machines, ice makers, coffee equipment - bring their own air-gap, check-valve, or vacuum-breaker requirements.
Accessibility
Learn the ICC A117.1 numbers: lavatory rim or countertop at 34 in. maximum, knee clearance 27 in. high and 29 in. from the finished floor, water closet seat height 17–19 in., clear floor space 30 by 48 in., and reach ranges within 15–48 in. Urinal rim height is also limited. These dimensions are favorite question material because they are easy to misremember.
Traps in questions
Confusing flow rate units (gpm versus gpf), assuming an accessible fixture is just a lower fixture, ignoring the required primer on a floor drain, and overlooking backflow protection on a hose-threaded outlet.
Worked example
A 1.28 gpf water closet replaces a 1.6 gpf unit flushed 3,000 times per year. Savings = 0.32 gal × 3,000 = 960 gallons per year per fixture.