Weak on both hot and cold
The shower never really gets forceful, and the problem stays about the same no matter the temperature setting.
Start here: Start with the shower head and its inlet screen. That is the most likely restriction.
Shower pressure troubleshooting
Water Pressure Low in Shower Only
Direct answer: If the sink and tub still have normal flow but the shower feels weak, the problem is usually at the shower head or inside the shower valve, not in the whole house plumbing.
Most likely: The most common cause is mineral buildup in the shower head or a clogged screen where the shower head threads onto the shower arm.
Separate a weak spray from a true supply problem right away. If every fixture in the house is weak, this is not a shower-only issue. If only the shower is weak, start at the shower head, then move back to the valve if the head is clear and flow is still poor. Reality check: a shower can feel low-pressure even when the plumbing is fine if the spray holes are half plugged. Common wrong move: replacing the shower head before checking the inlet screen and the valve setting behind the trim.
Don’t start with: Do not start by opening the wall or buying a new valve. Most low-pressure shower calls get solved at the shower head first.
Only the shower is weakCompare hot and cold at the bathroom sink or tub spout first so you know whether this is fixture-specific or house-wide.
Weak spray, not no waterRemove and inspect the shower head before touching trim or assuming the valve is bad.
Last reviewed: 2026-04-05
What low shower pressure looks like
Weak mostly on hot water
Cold flow seems better, but pressure drops when you turn toward hot.
Start here: Look for a shower cartridge or pressure-balance spool issue after confirming the shower head is clear.
Pressure dropped suddenly
The shower used to feel normal, then got weak over a day or two or all at once.
Start here: Check for debris caught in the shower head or valve after recent plumbing work, a shutoff change, or a water interruption.
Tub spout is strong but shower head is weak
On a tub-shower setup, the tub fills normally but the shower spray is weak when you pull the diverter.
Start here: Focus on the shower head first, then the tub diverter if the head is clear and the spray still stays weak.
Most likely causes
1. Clogged shower head spray holes or inlet screen
This is the most common shower-only restriction, especially with hard water or after plumbing work stirred up debris.
Quick check: Unscrew the shower head and look for white crust, grit, or a small screen packed with sediment.
2. Flow restrictor or internal shower head insert partly blocked
A shower head can look clean outside but still have a blocked insert that chokes flow.
Quick check: With the shower head removed, briefly run water from the shower arm into a bucket. Strong flow there points back to the shower head assembly.
3. Shower cartridge not opening fully or pressure-balance spool sticking
If the shower head is clear but flow is still weak, the valve may not be passing full volume, often worse on the hot side.
Quick check: Compare hot and cold performance. If one side is much weaker, the cartridge is a stronger suspect.
4. Tub diverter not sending full flow to the shower head
On tub-shower combinations, a worn diverter can bleed water back to the tub and leave the shower weak.
Quick check: Run the shower and watch the tub spout. A steady stream or heavy dribble from the spout means the diverter is not sealing well.
Step-by-step fix
Step 1: Confirm this is really a shower-only problem
You do not want to chase a shower part when the real issue is a supply problem affecting more than one fixture.
- Turn on the bathroom sink cold and hot and note whether flow looks normal.
- If you have a tub spout on the same valve, run the tub spout and compare its flow to the shower.
- If other fixtures in the house are also weak, stop here and treat it as a broader plumbing pressure problem instead of a shower problem.
- If only the shower is weak, continue with the shower head checks.
Next move: You confirmed the problem is isolated to the shower assembly, which keeps the repair focused and cheaper. If multiple fixtures are weak, the restriction is likely upstream and not at the shower head or trim.
What to conclude: Normal flow elsewhere means the shower head, shower valve, or tub diverter is the likely trouble spot.
Stop if:
- Water pressure is low at several fixtures in the house.
- You find active leaking behind the wall, under the tub, or at the ceiling below.
- The shower arm is loose in the wall or looks cracked.
Step 2: Remove the shower head and check the easy restriction points
Most shower-only low pressure comes from buildup or debris right at the outlet end.
- Wrap the shower head nut with a rag and unscrew it carefully so you do not scar the finish.
- Look inside the shower head inlet for a screen, rubber washer, grit, or white mineral scale.
- Rinse loose debris out under a sink faucet if possible.
- Soak the shower head in warm water and vinegar if mineral buildup is visible and the finish is in good shape for a mild soak, then rinse well.
- Clean spray holes gently with a soft brush or wooden toothpick, not a metal pick that can damage them.
Next move: If the spray improves after cleaning and reinstalling, the restriction was in the shower head or inlet screen. If the shower head looks clear or cleaning changes nothing, test flow from the bare shower arm next.
What to conclude: A clogged shower head is the simplest and most common fix, and it is worth ruling out before touching the valve.
Step 3: Test flow from the shower arm before blaming the valve
This separates a bad shower head from a weak supply through the valve.
- With the shower head still off, point the bare shower arm into a bucket or tub and briefly turn the shower on.
- Watch whether water comes out with strong, full flow or still looks weak.
- If flow from the bare arm is strong, the shower head assembly is the restriction even if it looked mostly clean.
- If flow from the bare arm is still weak, move your attention back to the valve or diverter.
Next move: Strong flow from the bare arm means replacing the shower head is reasonable if cleaning did not restore performance. Weak flow from the bare arm means the problem is upstream of the shower head.
Step 4: Check for a valve or diverter problem
Once the shower head is ruled out, the next likely restriction is inside the shower valve or at the tub diverter on combo units.
- On a tub-shower combo, run the shower and look at the tub spout. A heavy dribble or stream from the spout points to a worn diverter.
- Compare pressure on the cold side versus the hot side. If hot is much weaker, the shower cartridge is a stronger suspect.
- If the handle travel feels limited, remove trim as needed and check whether the handle adapter or limit stop is preventing full opening.
- If recent plumbing work was done, cycle the valve a few times because debris can lodge in the cartridge or balancing section.
Next move: If you find strong tub-spout bypass or one-sided weakness, you have a solid reason to service the diverter or shower cartridge. If both sides are weak, the tub spout is not bypassing, and the shower arm flow is still poor, the valve may need deeper service or pro diagnosis.
Step 5: Make the repair that matches what you found
At this point you should know whether the fix is at the shower head, the cartridge, or the tub diverter.
- If bare-arm flow was strong, reinstall the cleaned shower head or replace it with a matching shower head if cleaning did not restore pressure.
- If hot-side or mixed-flow weakness points to the valve, shut off water and replace the shower cartridge that matches your valve.
- If a tub-shower diverter is bleeding water back to the spout, repair or replace the tub diverter component that controls shower flow.
- After reassembly, run cold, hot, and mixed water and confirm the spray is stronger and stable.
A good result: You restored normal shower flow without opening the wall or replacing parts blindly.
If not: If pressure is still poor after the matching repair, the valve body may be obstructed or there may be a hidden supply issue that needs a plumber.
What to conclude: A successful repair confirms the restriction was local to the shower assembly. If not, the problem is deeper than the easy service parts.
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FAQ
Why is my shower pressure low but the sink pressure is fine?
That usually means the restriction is local to the shower. The most common spots are the shower head spray holes, the inlet screen, or the shower cartridge.
How do I know if the shower head is the problem?
Remove the shower head and briefly run water from the bare shower arm into a bucket or tub. If flow is strong there, the shower head assembly is the restriction.
Can a bad shower cartridge cause low pressure?
Yes. A worn or debris-packed shower cartridge can limit flow, often more on the hot side or when the handle is near mixed temperature.
Why is my tub spout strong but the shower weak?
That usually points to the shower head or, on a tub-shower combo, a diverter that is not sending full flow up to the shower head.
Should I remove the flow restrictor from my shower head?
Not as a first move. Low pressure is more often caused by buildup or debris than by the restrictor itself. Clean and test first so you do not change the shower head unnecessarily.
When should I call a plumber for low shower pressure?
Call if the shower arm is loose in the wall, the valve will not shut off, the cartridge is seized, pressure is still weak after the shower head and cartridge checks, or you see leaking behind the wall.