Fixture Installation

Every toilet, faucet, and showerhead sold in the U.S. must meet a federal maximum water-use standard, and the EPA's voluntary WaterSense label identifies products that use meaningfully less.

The gap between an older toilet and a new WaterSense model is large enough that replacing a single pre-1994 toilet can measurably lower a household's water use without any change in how the fixture performs day to day. WaterSense certification requires fixtures to pass EPA performance testing in addition to meeting the flow limit, so the lower number is not simply a weaker flush or a thinner stream, it is a fixture engineered to do the same job with less water.

The standard is not frozen in place. The EPA has drafted a tighter Version 2.0 WaterSense specification that would lower the bathroom faucet maximum from 1.5 to 1.2 gallons per minute, though that revision is currently paused for further review rather than in effect. Until it is finalized, 1.5 gallons per minute remains the current WaterSense threshold for bathroom faucets.

Toilets, in particular, are built around a standard rough-in: the distance from the finished wall behind the toilet to the center of the drain and closet bolts. Most toilets sold in the U.S. are made for a 12-inch rough-in; some models are made for a 10-inch or 14-inch rough-in for bathrooms with unusual layouts or older plumbing. Before buying a replacement toilet, measure the existing rough-in and match it to the new fixture's own specification sheet. A mismatch means the toilet will not sit flush against the wall, or the tank will not clear it.

Faucets, sinks, and tub and shower valves have their own rough-in requirements for supply line spacing and hole patterns, which is why swapping a fixture for one from a different manufacturer or a different era sometimes takes more work than expected.

Standard toilets sit around 15 inches from floor to seat. Comfort-height, or chair-height, toilets are taller, and the U.S. Access Board's accessibility guidelines call for accessible water closets with a seat 17 to 19 inches above the floor, grab bars mounted 33 to 36 inches above the floor, and a clear floor space of at least 60 inches wide by 56 inches deep in front of the fixture.

You do not need to meet full accessibility code to benefit from a comfort-height toilet. Many homeowners choose one simply because it is easier to sit down and stand up from, particularly for older adults or anyone recovering from surgery.

The accessible clearance zone in front of a toilet is meant to stay open for a wheelchair transfer, and the accessibility guidelines only allow a short list of items to project into it: the toilet itself, grab bars, a toilet paper dispenser, a seat cover dispenser, a coat hook, a shelf, or a sanitary napkin disposal unit. A second fixture, a cabinet, or anything else has to stay outside that footprint, which is worth checking before finalizing a small bathroom layout.

The Uniform Plumbing Code requires shower and tub-shower valves to be pressure-balancing or thermostatic mixing valves certified to ASSE 1016, which automatically compensate when someone flushes a toilet or starts the dishwasher so the shower does not suddenly run scalding hot or ice cold. A related standard, ASSE 1070, covers point-of-use temperature-limiting devices for sinks, lavatories, and bathtubs.

The U.S. Consumer Product Safety Commission has documented how quickly hot water causes serious burns: an adult can suffer a third-degree burn after 2 seconds at 150 degrees Fahrenheit, 6 seconds at 140 degrees, or 30 seconds at 130 degrees. Even at 120 degrees, a five-minute exposure can cause a third-degree burn. CPSC recommends setting water heaters no higher than 120 degrees for this reason, in addition to the energy savings.

The two ASSE standards cover different points in the system, which is why a bathroom can need both. ASSE 1016 applies to the mixing valve itself, usually inside the wall at the shower or tub-shower control, and a single 1016-rated valve typically protects everything fed from it, including a hand-held or body spray on the same control. ASSE 1070 instead applies to a temperature-limiting device at an individual fixture, such as a lavatory faucet or a freestanding tub filler that is not already protected by a whole-valve system upstream.