Faucet only gives hot or only gives cold water

Symptoms

• Only hot or only cold comes out no matter the handle position
• Other faucets in the house have both temperatures
• Problem started suddenly, often after other plumbing work
• Handle can be turned fully but temperature doesn't change

Likely causes

• CommonShutoff valve closed on one sideSomeone may have closed a valve under the sink and not reopened it fully.
• CommonFailed or stuck single-handle cartridgeA cartridge can fail in a way that blocks one supply entirely.
• PossibleClogged supply line on one sideSediment can fully block a line, especially the hot side where scale builds faster.
• PossibleClosed valve elsewhere in the branch lineA valve further back, like at a water heater, could be shut.

What to do

1. Check both shutoff valves under the sink and make sure each is turned fully counterclockwise (open).
2. If it's the hot side missing, confirm the water heater's own shutoff valve is open too.
3. Turn off both valves, disconnect the supply line for the missing temperature, and check for flow directly from the valve into a cup.
4. If there's no flow from the valve itself, the blockage or shutoff is further back in the plumbing.
5. If the valve flows fine, the blockage or failure is inside the faucet; remove the handle and cartridge to inspect.
6. Clean out any visible debris in the cartridge's ports, or replace the cartridge if it's clearly failed.
7. Reassemble, restore water, and test both hot and cold fully.

Tools and parts

• Adjustable wrench
• Screwdriver

When to call a pro

Call a plumber if there's no flow from the shutoff valve itself, since the blockage may be further back in the supply line or at the water heater.

Safety