Replacing an under sink shut off valve is a common plumbing repair that homeowners may need to complete. The shut off valve controls water flow to the faucet and allows you to turn off water access when needed, such as when changing a faucet or repairing a leak. Over time, these valves can wear out or fail, requiring replacement. While this repair may seem daunting, it can easily be completed by most DIYers with some simple tools and by following these steps.
Page Contents
When to Replace an Under Sink Shut Off Valve
Here are some signs that it’s time to replace your shut off valve:
- The valve is stuck open or closed and cannot be turned on/off.
- The valve handle is stripped or damaged and can no longer be gripped to turn.
- The valve leaks constantly, even when in the closed position.
- You need to frequently tighten the packing nut to stop drips.
- Water flow through the valve is reduced, indicating buildup due to hard water deposits or sediment.
Replacing the valve when you first notice these issues can prevent more serious leaks or damage further down the line.
Tools and Materials Needed
Replacing a shut off valve is a straightforward project that can be completed with some basic tools and a new valve:
- Adjustable wrench
- Pipe wrench
- Bucket
- Rag
- Safety glasses
- New ball valve shut off compatible with your pipes
Make sure to purchase a valve designed for under sink installation. It should have connectors to match the size of your supply lines (usually 1/2″ or 3/8″ compression fittings). Choosing a quarter-turn ball valve model allows water flow to be easily turned on and off.
Shutting Off the Water Supply
Before replacing the bad valve, you need to shut off the water supply to the sink. This prevents water from spraying out when you disconnect the lines.
There are a few ways to do this:
Shut Off Valves Under the Sink
If you have shut off valves located under the sink for both hot and cold water lines, simply turn them clockwise to shut off water flow. These valves look similar to the one you are replacing but control the entire water supply to the sink.
Main Shut Off Valve
If you don’t have individual shut offs under the sink, turn off the main water valve for the house. This is usually located near the front of the house where the main water line comes in or by the water meter. Turn the valve clockwise to shut off water.
Turn Off Water at Hot Water Heater
For sinks with only a hot water line, turn off the water valve on the hot water heater to stop hot water flow to the faucet. Make sure valves feeding other sinks and appliances remain open.
With the water turned off, you can now safely work on replacing the bad shut off valve. Place a bucket under the work area to catch any water still left in the pipes.
Replacing the Valve
Follow these steps to remove the old valve and install a new one:
Step 1: Disconnect Supply Lines
Start by loosening the fittings connecting the supply lines to the old valve. Place a wrench on the nut connecting the line to the valve and turn counter-clockwise to loosen.
Unscrew the nut completely and pull the supply line off the old valve. You may need to wiggle it free if it’s stuck due to mineral deposits. Repeat for both hot and cold water lines.
Step 2: Remove Bad Valve
With the supply lines disconnected, now loosen and unscrew the compression nuts holding the valve to the shut off valve body. There is one on the hot and cold water inlet and outlet.
Slide the compression nuts and rings off the pipe and remove the bad valve. Make sure to take note of the valve’s original orientation.
Step 3: Install New Valve
Install the new ball valve by first sliding on the compression nuts and rings in the same direction as on the old valve. The rings should face the valve body.
Insert the pipes into the valve and tighten the compression nuts using your adjustable wrench. Do not overtighten.
Make sure the new valve is positioned exactly the same as the old one. The valve handle should be upright and easy to access.
Step 4: Reconnect Supply Lines
With the new valve firmly installed, realign the supply lines. Thread the compression nut of each supply line onto its fitting on the valve. Tighten using your wrench, but do not overtighten.
Step 5: Turn Water Back On
Once the lines are reconnected, turn the main water supply back on. Check for leaks at the valve fittings and supply line connections. Tighten if necessary.
Turn the valve on and off a few times to make sure it operates smoothly. Finally, turn on the faucet to test water flow and check for drips.
Troubleshooting Tips
Follow these troubleshooting tips if you encounter any problems during the valve replacement process:
Leaks from Valve Fittings
– Tighten compression nuts further with wrench
– Ensure pipe is fully inserted into valve
– Replace compression ring if damaged
Valve Handle is Stiff/Hard to Turn
– Valve may be overtightened – loosen slightly
– Impurities in valve – turn handle multiple times to flush debris
– Replace valve if issue persists
Reduced Water Flow
– Check for kinks/blockages in supply lines
– Shut off water, disconnect supply lines and flush to remove sediment
– Replace valve if flow remains reduced
Conclusion
Replacing an under sink shut off valve is an essential repair that even inexperienced DIYers can tackle. With the right materials, proper precautions like turning off water supply, and following the step-by-step process, you can replace a faulty valve and restore proper water flow and shut off capability to your sink. Paying attention to leak checks and valve operation during reassembly will ensure you get years of reliable performance from the new shut off valve.
Frequently Asked Questions
How do I know what size replacement valve to get?
Check the piping under your sink to determine the correct valve size needed. Most sinks use standard 1/2″ or 3/8″ supply lines and matching shut off valves.Purchase a valve with compression fittings to match your pipe diameter.
Can I replace a shut off valve myself?
Yes, replacing a shut off valve is a very approachable DIY project. With basic tools and materials, and by carefully following the steps, most homeowners can remove an old under sink valve and install a new one. No plumbing experience is necessary.
What type of new valve should I use?
Opt for a 1/4-turn ball valve when replacing an under sink shut off. This style allows water flow to be easily turned on and off with a 90 degree turn of the handle. Choose a durable metal valve over plastic models for longer performance.
What if I can’t find the main water shut off valve?
Turn off the water supply at each appliance until you locate the main shut off for the house. Check near the water meter, basement, garage, or where the main water line enters the home. If needed, contact a plumber to help identify the valve.
Can I replace a shut off valve without turning off water?
It is not recommended. You run the risk of water damage or injury from pressurized water spewing out. Always turn off main or under sink valves prior to replacing a shut off valve on a live line.
Replacing an Under Sink Shut Off Valve: Step-by-Step
Follow this comprehensive step-by-step guide to successfully replace a faulty under sink shut off valve:
Step 1) Turn Off Water Supply
Locate water shut off valves under sink or main valve for house. Turn clockwise to shut off water flow completely.
Step 2) Disconnect Supply Lines
Loosen compression nuts at top and bottom of old valve with wrench. Unscrew nuts and detach supply lines.
Step 3) Remove Old Valve
Unscrew and remove compression nuts and rings from valve. Pull valve out, being careful not to damage pipes.
Step 4) Position New Valve
Align and insert new valve onto pipes in same direction as old valve. Note handle orientation.
Step 5) Secure New Valve
Slide compression nuts and rings over valve fittings. Hand tighten nuts first then fully tighten with wrench.
Step 6) Reattach Supply Lines
Align supply lines with valve ports. Thread on compression nuts and tighten by hand then with wrench.
Step 7) Turn Water Back On
Slowly turn water at main or under sink back on. Inspect for leaks. Tighten any joints or connections that drip.
Step 8) Test New Valve
Turn new valve on/off multiple times. Check faucet for proper water flow. Monitor for additional leaks over next 24 hours.
Under Sink Shut Off Valve Replacement Costs
Replacing an under sink shut off valve is one of the most affordable plumbing repairs. Here are typical parts and labor costs:
| Expense | Typical Cost |
|---|---|
| Shut off valve (1/2″ or 3/8″) | $5 – $30 |
| Misc. supplies (fittings, pipe, tools) | $10 – $30 |
| Plumber hourly rate | $45 – $150 per hour |
While prices vary based on valve type and project complexity, most homeowners spend $10 to $50 total on parts to do it themselves. Hiring a plumber typically adds $40 to $250 or more, depending on hourly rates and time required.
Doing the repair yourself can save a significant amount over pro installation. With basic DIY skills and tools, you can replace a shut off valve in under an hour.
Reasons to Hire a Plumber
Although a DIY valve replacement project can save money, there are some situations when it’s better to call a professional plumber:
- No main or under sink shut off valve can be located to turn off water
- Pipes are corroded or otherwise damaged and need replacement
- The sink has a tricky configuration making access difficult
- You encounter leaks or other issues you can’t resolve
- You lack the skills, tools, or confidence for the project
Hiring a pro to replace the valve ensures the job is done right the first time. While it costs more upfront, it prevents expensive water damage or complex repairs down the road.
Preventing Future Shut Off Valve Failure
To maximize the lifespan of your new replacement shut off valve, keep these maintenance tips in mind:
- Periodically inspect valve for drips or leaks
- Ensure valve is fully open when water is in use
- Exercise valve every few months to prevent sticking
- Avoid slamming or knocking the valve with objects
- Replace valve at first signs of failure like leaking
Proactive maintenance helps prevent premature wear and extends the valve’s working life. Consider periodic replacement every 5-10 years as part of routine plumbing upkeep.
Conclusion
Replacing a faulty under sink shut off valve is a common DIY plumbing task that nearly any homeowner can tackle. Following the proper steps for shutting off water, removing the bad valve, installing the new one, and reattaching supply lines allows even beginners to complete this repair. The project requires only simple tools and an inexpensive replacement valve available at any hardware store.
Paying close attention to properly securing fittings and checking for leaks ensures your new shut off valve reliably controls water flow for years of leak-free use. With basic skills and the right precautions, you can avoid the expense of a plumber to repair or replace a worn out under sink shut off valve.