Quick Answer:
If the house shutoff is showing stiffness when you turn it, lets water trickle after closing, or the stem wiggles side-to-side, those are signs it may be near the end of its service life. Do a few simple checks at the valve: test how the stem moves, look for internal leakage by watching flow after closing, and confirm the seat actually seals when the valve is closed. If any of those checks fail, plan a repair or replacement before an emergency.
Why This Happens
- Mineral deposits and grit wear the sealing surfaces and seat over time.
- Corrosion can pit metal parts and weaken the stem or packing.
- Repeated use and age can loosen connections or deform internal parts so the valve no longer seats fully.
- Poor lubrication or debris in the water can make the valve stiff or cause internal leakage.
Step-by-Step What to Do
1. Prepare and stay safe
- Gather a flashlight, towels or a bucket, and someone to help watch fixtures while you operate the valve.
- Turn off sensitive appliances (water softener, irrigation) or unplug electric devices near the water line if you expect water spillage.
- Work slowly and don’t apply excessive force to a stuck valve.
2. Check stem play
- With the valve in the closed position, place your hand on the stem (the rotating shaft) and gently try to move it side-to-side and in-and-out.
- Small movement from packing is normal; obvious wobble or looseness means the stem, nut, or joint may be worn or broken and the valve can fail under load.
3. Check for internal leakage
- Close the valve fully, then go to an indoor fixture (tub, sink) and run the tap briefly. If water still flows or there’s a steady drip, the valve is leaking internally.
- Another method: note the home water meter reading, close the valve, wait 10–15 minutes, and recheck. Any continued flow suggests internal leakage past the seat.
4. Test seat closure performance
- Slowly open the valve fully, then close it fully while watching a fixture or the meter. The flow should stop promptly when fully closed.
- If flow reduces but does not stop, or if closing requires multiple turns and still lets water through, the seat is likely worn and the valve won’t seal properly — a clear sign of end-of-life.
- If you notice the valve “won’t close completely,” that is a symptom that typically needs repair or replacement rather than more adjustment.
5. Note valve type and condition
- Look at the valve style and material. Some failure modes are more common with certain designs. If you’re unsure whether a gate or a ball type is better for your setup, review comparisons like gate valve vs ball valve to understand typical weaknesses and replacement choices.
What Not to Do
- Do not wait for failure during emergency — address signs of trouble now.
- Do not force a frozen or very stiff valve; forcing can break the stem or packing and make the leak worse.
- Do not attempt major repairs on a buried or corroded valve unless you have proper tools and experience; that can create a larger leak.
- Do not use open flames or improvised heating to loosen a valve; that’s dangerous and unnecessary.
When to Call a Professional
- If the valve will not stop flow at all, call a plumber immediately — that’s not safe to leave.
- If the stem is severely loose, corroded, stripped, or the valve leaks under pressure, a professional can assess whether repair or replacement is needed.
- Have a pro handle buried shutoffs, service lines with difficult access, or when a permit is required for replacement work.
- If you want to understand long-term options (different valve types, relocation, or upgrades), consult a plumber to compare alternatives such as problems that cause a main shutoff to “won’t close completely” after years of use.
Safety Notes
- Always move valves slowly to avoid water hammer and sudden pressure change.
- Keep electrical equipment and outlets protected when working near water.
- Wear gloves and eye protection if you expect corrosion or pressurized spray.
- If a test produces a significant leak, shut off secondary valves where possible and call for help rather than trying risky emergency fixes.
Common Homeowner Questions
- How often should I test the shutoff?
Check and exercise it every 6–12 months so you notice problems before an emergency. - Can I replace the valve myself?
If you’re not experienced with plumbing and permits, it’s safer to hire a plumber — replacements can involve cutting and soldering, or shutting down the street supply. - What if the valve leaks at the stem?
A minor stem drip may be tightened or packed, but persistent or heavy leaks mean the valve should be serviced or replaced by a professional.