Why won't my angle stop valve shut off all the way?

Most older angle stops are multi-turn valves. BrassCraft, a major maker of these stops, describes its multi-turn valves this way: "With a few turns of the valve handle, you are able to stop the flow of water leading to the plumbing fixture." Inside, the handle turns a stem. The parts diagram in BrassCraft's installation instructions shows the stem assembly and a rubber bibb washer. As you turn the handle, the stem pushes that washer down onto a seat inside the valve body, and the washer blocks the water.

That design only works if the washer and the seat are in good shape. When either one isn't, water slips past, even with the handle turned tight. The common reasons:

• A worn or damaged washer. Rubber can wear, crack or lose its shape over years in the valve. A washer that can't press flat against the seat can't seal.
• Buildup on the seat. Minerals and debris can collect where the washer lands. Phoenix water is hard. The city's 2025 water quality report lists hardness of 10 to 17.6 grains per gallon and says hard water "can cause some types of scaling in pipes and water heaters, and on plumbing fixtures such as faucets and showerheads."
• Long periods of non-use. Stops often sit untouched for years. When you finally turn one, the washer and seat haven't moved in a long time.

### What about a valve that leaks at the handle?

That's a different problem. Water coming out around the stem, just under the handle, points to the packing, not the washer. See why a shut-off valve leaks at the handle for that fix.

Some multi-turn stops can be rebuilt. BrassCraft sells a multi-turn stop stem repair kit, and says it "is for angle and straight style multi-turn valves." If your stop is a BrassCraft multi-turn and the body is in good shape, a new stem assembly can bring it back.

Most of the time, though, replacement is the better call. A rebuild puts a new stem in an old body, on a seat that may still be worn or scaled. BrassCraft's own instructions set a clear line for when a stop should go. They say to "inspect annually, replace if damaged, deterioration or corrosion is detected," and warn that failing to do so "may result in product failure and property damage." A stop that no longer closes is a stop that's already failed at its one job.

### Why a quarter-turn stop is the usual upgrade

A quarter-turn stop uses a ball instead of a washer. BrassCraft says that "With a 90-degree turn of the valve handle, you are able to stop the flow of water leading to the plumbing fixture." Its product literature says its KT Series quarter-turn ball stops use a precision-machined brass ball "mated with PTFE seats to provide smooth operation even after long periods of non-use."

That last part matters most for a stop. You might not touch it for five or ten years, and then need it to work on the first try.

There are a few things to know about quarter-turn stops:

• Use it fully open or fully closed. BrassCraft's instructions say the stop "must be used in the fully opened or fully closed position." Don't leave it halfway to turn down the flow.
• Recirculating hot water lines have limits. BrassCraft says not to use its G2 quarter-turn or multi-turn stops on recirculation systems exceeding 115°F.
• Match the connection. Stops come in compression, sweat (soldered), threaded, PEX and CPVC versions. BrassCraft's line includes all of these. The new stop has to match the pipe coming out of your wall or floor.

The job is short, but the details depend on your pipe. At a high level:

1. 1Shut off the water to the house. You can't isolate a stop that won't close, so the main valve has to go off. Check that yours works before you start. Our guide to testing your main water shut-off valve walks through it.
2. 2Open a faucet to drain the line and relieve pressure.
3. 3Disconnect the supply line from the old stop.
4. 4Remove the old stop. BrassCraft's diagrams show the three common ways a stop attaches: a compression nut and sleeve, threads on a pipe nipple, or solder on a copper stub out. A compression stop comes off by loosening its nut. A soldered one has to be heated off.
5. 5Install the new stop to match the pipe. For compression stops, BrassCraft's instructions warn: "DO NOT OVERTIGHTEN as this could lead to future failure."
6. 6Turn the water back on slowly and check every joint for drips.

For the full steps by pipe type, see how to replace a toilet shut-off valve. The same process applies to sink stops.

### Soldered stops need extra care

Removing a soldered stop means heating the joint, and installing a new sweat stop means soldering one on. BrassCraft's instructions say that for a multi-turn sweat stop, you remove the complete stem assembly first so the heat doesn't damage the washer. For its G2 quarter-turn stops, they say not to sweat within 12 inches of the valve. That's work many homeowners leave to a plumber, especially with cabinets and walls close by.

Yes, in most places in a home. Phoenix's adopted plumbing code, Section 606.2, requires shutoff valves "On the fixture supply to each plumbing fixture other than bathtubs and showers in one- and two-family residential occupancies." It also requires them on the supply to each sill cock and to each appliance or piece of mechanical equipment. Section 606.3 adds that access "shall be provided to all full-open valves and shutoff valves."

So a sink or toilet should have a working stop you can reach. If a stop is buried behind a cabinet back or won't close, the fixture has lost the protection code expects it to have.

A stop that won't close is worth fixing before you need it in a hurry. Call a plumber when:

• The main house valve is hard to turn or doesn't close either.
• The stop is soldered on, or the pipe behind it is corroded.
• Several stops in the house are failing. Replacing them all at once saves shutting the water off again and again.
• You see green or white crust on the pipe at the wall, which can mean a slow leak.

For a quick fix while you wait, you can still shut off water to a fixture at the house valve. Our page on how to shut off water to a fixture covers the options.

HQ replaces angle stops and main valves throughout the Valley. We're licensed and insured, available 24/7, and every estimate is free with upfront pricing.