No cold water at one faucet only
Hot water runs normally, but the cold side gives nothing or just a dribble at one sink.
Start here: Check whether the cold stop valve is fully open and whether the cold supply line is kinked or crushed.
Faucet Troubleshooting
Faucet Cold Water Not Working
Direct answer: When a faucet loses cold water but hot still works, the problem is usually on the cold side only: a partly closed stop valve, a kinked or clogged cold supply line, or a faucet cartridge that is blocked or failed on the cold port.
Most likely: Most often, the cold shutoff under the sink is not fully open, the cold supply line is restricted, or the faucet cartridge has debris packed into it after plumbing work or mineral buildup.
Start under the sink and work forward. If other cold fixtures in the house work normally, this is usually a local faucet problem, not a whole-house issue. Reality check: a faucet that suddenly loses only cold water after someone stored items under the sink often has a bumped stop valve or a pinched line. Common wrong move: buying a new faucet before checking whether the cold stop is half closed or the cartridge inlet is plugged with grit.
Don’t start with: Do not start by replacing the whole faucet. First find out whether the cold water is missing before it reaches the faucet or only after it gets into the faucet body.
Hot works, cold does notCheck the cold stop valve and cold supply line under the sink before opening the faucet.
No cold at just one faucetTreat it as a local restriction until you prove the house cold supply is affected too.
Last reviewed: 2026-04-04
What kind of cold-water failure do you have?
Cold water is weak but not fully dead
The cold side still runs, but much weaker than hot, often with sputtering or uneven flow.
Start here: Look for a partly closed stop valve, debris in the faucet cartridge, or a clogged faucet aerator if both hot and cold are weak at the spout.
Cold quit right after plumbing work or a shutoff
The faucet worked before, then lost cold after a valve was closed, a water heater was changed, or the water was shut off to the house.
Start here: Suspect debris in the cold faucet cartridge or cold supply line first, especially if other fixtures are acting gritty too.
No cold at several fixtures
More than one faucet has no cold water, or the toilet and other cold fixtures seem affected too.
Start here: Stop treating this as a faucet-only problem and check the house cold supply, main valve position, or a frozen line.
Most likely causes
1. Cold stop valve under the sink is closed or partly closed
This is the fastest, most common local cause, especially after cleaning under the sink, recent work, or a curious hand turning the valve.
Quick check: Look under the sink and confirm the cold shutoff handle is fully open and not loose on the stem.
2. Cold faucet supply line is kinked, crushed, or clogged
A bent braided line or debris caught in the line can starve the faucet even when the stop valve looks open.
Quick check: Trace the cold faucet supply line from the stop valve to the faucet and look for a sharp bend, flattening, or signs of recent disturbance.
3. Faucet cartridge is blocked or failed on the cold side
Single-handle and many two-handle faucets rely on internal passages that can plug with grit or scale, especially after a shutoff or plumbing repair.
Quick check: If strong cold water comes out of the disconnected supply line but not through the faucet, the restriction is likely inside the faucet cartridge or cold-side valve body.
4. House cold supply problem or frozen branch line
If more than one fixture has lost cold water, the faucet is usually not the real problem.
Quick check: Test another nearby cold fixture. If that one is weak or dead too, move upstream to the branch or whole-house supply.
Step-by-step fix
Step 1: Confirm this is a faucet problem, not a house cold-water problem
You do not want to tear into the faucet if the cold supply is missing upstream.
- Turn on cold water at another faucet nearby, then at a fixture farther away in the house.
- Flush a toilet or open another cold-only fixture if available to see whether cold water is present elsewhere.
- Note whether the problem is only this faucet, only this room, or multiple fixtures.
Next move: If other fixtures have normal cold water, stay focused on this faucet and its local shutoff, supply line, or cartridge. If several fixtures have no cold water, stop here and trace the branch line, main valve position, or possible freeze issue instead of replacing faucet parts.
What to conclude: A single dead cold side points to a local faucet-side restriction. Multiple affected fixtures point upstream.
Stop if:
- More than one fixture has lost cold water.
- You suspect a frozen pipe in the wall or cabinet.
- You find active leaking while testing other fixtures.
Step 2: Check the cold stop valve under the sink
A partly closed or failed stop valve is common, easy to miss, and safer to check before disconnecting anything.
- Find the cold shutoff under the sink. It is usually on the right supply line for the cold side, but verify by tracing the line to the faucet.
- Turn the valve gently clockwise until it stops, then back it fully open. Do not force it.
- Watch the valve while you move it. Look for dripping at the stem, packing nut, or outlet.
- Run the faucet cold side again and compare flow.
Next move: If cold flow returns, the valve was not fully open or had a sticky spot. Leave it fully open and monitor it for seepage. If nothing changes, keep going. The restriction may be in the supply line or inside the faucet.
What to conclude: A working adjustment here means the problem was before the faucet. No change keeps the diagnosis local but not yet confirmed.
Step 3: Inspect the cold faucet supply line for a kink or blockage
A damaged or plugged cold supply line can shut the faucet down even when the stop valve is open.
- Trace the cold faucet supply line from the stop valve to the faucet body.
- Look for a sharp bend, crushed braid, rubbing against stored items, or a line twisted during recent work.
- Place a towel and small container under the stop valve connection.
- Shut the cold stop valve, disconnect the cold faucet supply line at the faucet or valve end, then briefly crack the stop valve open into the container to check flow.
- If flow from the stop valve is strong but the line itself seems restricted, inspect the line for internal collapse or debris.
Next move: If straightening the line or replacing a damaged cold faucet supply line restores flow, the problem was in the local line. If strong cold water reaches the disconnected line or faucet connection but still will not pass through the faucet, move to the cartridge check.
Step 4: Check for faucet blockage at the outlet, then suspect the faucet cartridge
Debris can lodge at the aerator or inside the cartridge, and the cartridge is the main faucet-side failure point when only one temperature is affected.
- Remove the faucet aerator and rinse out grit or scale if the faucet has one.
- Run the faucet briefly with the aerator off and compare hot and cold flow.
- If the cold side is still dead or much weaker while hot is normal, shut off both faucet stops.
- Remove the handle and access the faucet cartridge or cold-side stem assembly according to the faucet style.
- Inspect for torn seals, packed debris, mineral crust, or a damaged cartridge body. Rinse loose debris from the faucet body if accessible and safe to do so.
Next move: If cleaning the aerator or clearing debris from the cartridge area restores cold flow, reassemble and test for smooth operation. If the cartridge is visibly damaged, stiff, or still blocks cold flow after cleaning, replace the faucet cartridge with the correct match for your faucet.
Step 5: Reassemble, test, and decide whether this is a cartridge repair or a bigger plumbing issue
You want to confirm the fix under normal use and catch leaks before putting the cabinet back together.
- Reinstall the cartridge or new cartridge, reassemble the handle, and reopen the stop valves slowly.
- Run cold only, then hot only, then mixed water for at least a minute.
- Check under the sink for leaks at the stop valve, supply line connections, and faucet shanks.
- If cold flow is still missing after a confirmed open stop valve and good supply to the faucet, stop replacing random parts and move to a plumber for valve-body damage or hidden branch blockage.
A good result: If cold flow is back and steady with no leaks, the repair is complete.
If not: If the faucet still will not pass cold water after a verified supply and cartridge replacement, the faucet body or nearby branch piping needs closer diagnosis.
What to conclude: A successful retest confirms the restriction was local. A failed retest after good supply and cartridge work points beyond simple DIY parts swapping.
Replacement Parts
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FAQ
Why does my faucet have hot water but no cold water?
That usually means the problem is isolated to the cold side. The most common causes are a partly closed cold stop valve, a kinked or clogged cold faucet supply line, or a faucet cartridge blocked on the cold inlet.
Can a bad faucet cartridge stop only the cold water?
Yes. On many faucets, the cartridge has separate internal paths for hot and cold. Debris or wear can block one side while the other still works normally.
Should I replace the whole faucet if the cold side stopped working?
Not first. If other cold fixtures work, check the cold stop valve, the cold faucet supply line, and the faucet cartridge before replacing the whole faucet. Whole-faucet replacement is usually not the first smart move here.
What if no cold water comes out of the disconnected supply line?
Then the problem is upstream of the faucet. Look at the cold stop valve first. If the valve is open but flow is still weak or absent, the issue may be in the branch supply or a frozen or blocked line.
Why did the cold side stop working right after plumbing work?
Debris is the usual culprit. When water is shut off and turned back on, grit and mineral flakes can break loose and lodge in the faucet cartridge or aerator, especially on the cold side.
Can a clogged aerator make it seem like the cold water is not working?
Sometimes, but usually it affects overall spout flow more than just one temperature. It is still worth checking because it is quick, safe, and often catches debris after plumbing work.