Shutoff valve replacement

Why shutoffs matter

Every sink and toilet should have its own shutoff, and the house should have a main shutoff that closes completely. When a supply line bursts or a toilet overflows, a working valve stops the water in seconds.

A valve that will not turn, or that leaks when it does, turns a small problem into a flooded floor. Many valves in older San Gabriel Valley homes have not been touched in decades, and their rubber washers have hardened.

Signs a valve needs replacing

• The handle will not turn, or turns but water keeps flowing.
• Water weeps from the packing nut around the stem when turned.
• Green or white crust on the valve body or compression nut.
• The valve is a saddle valve clamped onto a pipe, often used for old ice makers.
• The main gate valve handle spins without closing.

Multi-turn versus quarter-turn

Older compression stops use a stem and washer that close after several turns. Quarter-turn ball valves open or close with a 90-degree turn and are less likely to seize. When we replace a stop, we usually use a quarter-turn valve sized to the existing pipe, with a compression, threaded or push-fit connection depending on the pipe type and condition.

How we replace a stop

1. Shut off water at the main and drain the line.
2. Remove the old valve, cutting off old compression sleeves when they are stuck.
3. Clean and inspect the pipe stub.
4. Install the new valve with a new sleeve and nut, or thread it on with sealant.
5. Connect a new braided supply line.
6. Restore water and check for leaks under pressure.

On galvanized pipe nipples coming out of the wall, we check that the nipple is solid before threading a new valve on. A rusted nipple can snap, so we replace it when needed.

Main shutoff

Main shutoffs are usually near the front hose bib or at the meter. An accessible main gate valve can be replaced with a full-port ball valve when the pipe is in good shape. Valves at the meter on the street side belong to the water utility. If your main is buried, inside a wall or in poor condition, that is outside our scope.

Water loss from leaks

EPA WaterSense reports that "the average household's leaks can account for more than 9,300 gallons of water wasted every year." A weeping stop is a small contributor, but replacing it also protects cabinets and floors from slow damage.

Pipe types we see

Valley homes have copper, galvanized steel, CPVC and PEX, sometimes all in one house. Each takes its own valve connection: compression for copper, threaded for galvanized nipples, solvent or compression for CPVC, and crimp, expansion or push-fit for PEX. Matching the right valve to the pipe avoids future leaks.

Exercise your valves

Turning each shutoff closed and open once or twice a year keeps it from seizing. If a valve feels stiff or weeps, replace it while there is no emergency.

Toilet and sink supply lines

When we replace a stop, we replace the supply line too. Old plastic toilet lines and nuts crack, and solid chrome tubes are hard to reconnect without leaks. Braided lines are flexible and reliable.

Signs of a failing main

• Pressure drops when another fixture runs.
• The main handle is rusted or broken.
• Water drips from the stem when turned.
• The valve leaves a trickle when closed.

A main that does not close completely makes every other repair harder, since the house cannot be fully drained. Replacing it first is often the smart order of work.

Water saved by fixing small leaks

EPA WaterSense says "fixing easily corrected household water leaks can save homeowners about 10 percent on their water bills." Leaking stops are one of the easy fixes it has in mind.

More questions

How long does a stop replacement take? A single stop on accessible pipe is usually short; old galvanized nipples or stuck sleeves add time.

Should I label my valves? Yes. A tag on the main and each stop saves time in an emergency.

Valve sizes and supply lines

Most stops have a 1/2-inch inlet and a 3/8-inch compression outlet for faucets, or a 3/8-inch outlet with a toilet connection. Some older homes use 1/2-inch outlets to faucets. Matching the outlet size to the supply line avoids adapters, which add leak points. Dual-outlet stops serve two fixtures, such as a faucet and a dishwasher, from one valve.

When we replace stops, we also check the escutcheon plate on the wall. A loose or missing plate lets cabinet moisture and pests into the wall cavity, so we replace it with a split or deep escutcheon that covers the pipe opening.

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