Start at the valve under the sink, or at the one on the supply line behind the toilet. Put your hand on the handle. Whether it still does its job will show in the handle before it shows anywhere else.
What a shutoff valve is for
A shutoff valve stops water to a single fixture or appliance so you can work on it without closing the whole house. Most of the valves you find at a sink, a toilet, or a washer supply are quarter turn ball valves. The handle runs parallel to the pipe when water is on and crosses the pipe when it is off. Older whole house lines often have gate valves instead, which take several full turns and are the ones most likely to be stuck in place.
What to look and feel for
Check the handle first. It should move through its quarter turn with steady, even resistance and stop cleanly at both ends. Write down any of these:
- The handle is stiff, gritty, or needs extra force to start moving.
- The handle stops short or does not sit square with the pipe when open.
- The valve turns, but water still runs at the fixture when it should be off.
- A fine drip or a white or green crust collects at the stem or under the packing nut.
- The body of the valve or the joint above it shows a wet ring or a stain.
- The handle wobbles or turns loose on the stem.
How to test without forcing it
Do this when nothing is running and nobody is using the fixture. Close the valve gently until it stops. Then open it fully. Note how far it turned, how it felt, and whether the flow at the fixture changed as you expected. If the handle will not move, do not reach for a longer lever or a second wrench. Forcing an old valve can start a leak at the stem, and the leak is harder to manage once it has begun.
Write it into the record
Keep a short log beside the house paperwork. For each valve, record its location, its type, the install year if you know it, the season, and what you saw and felt. The log is your planning input. A valve that moved easily in an earlier season and now resists is a different fact from one that has always been stiff. The record shows which of the two you are looking at.
Who does what
Turning a valve to test it, cleaning around the handle, and wiping a drip to see whether it returns are reasonable checks for you. Replacing a valve, re-packing a stem, or cutting into a line is work for a plumber. Before the work starts, ask three things: whether the valve will be replaced or only re-packed, whether the line will need to be drained and where the water will be shut off, and whether the replacement matches the pipe material and size you have.
Read the paper before you lean on it
If a service contract or warranty is meant to pick up a valve repair, read how it defines the valve, what it counts as wear, and what it says about pre-existing conditions. Some papers treat valves as plumbing rather than as part of the appliance they feed, and the definitions decide the outcome. Check the terms in your own paper rather than assuming. The site's own tables list the published figures for each system.
Planning from the record
Once you have a few entries, you can plan. If the valves are gate valves from an older install, plan for a plumber to replace them while the wall is already open for other work. If they are quarter turn valves that still move cleanly, keep testing them each season and keep the log going. Either way, the log tells you what to ask for and when to ask.