Quick Answer:
After a repair that involved shutoffs or opening pipes, loose grit and residue commonly end up lodged in the showerhead screen or the valve cartridge. Start by removing and rinsing the showerhead screen/restrictor, then briefly flush the shower valve with the head off while protecting the wall and check for grit in the stream. If flushing does not restore normal flow, call a plumber.
Why This Happens
Work on nearby pipes or using shutoff valves disturbs mineral deposits, solder flux, pipe scale and bits of debris. That material travels a short distance and often gets trapped in the small mesh screen or the valve cartridge, reducing flow. If only one temperature is weak, the problem may be isolated to that supply line — for example, Low pressure only on the hot side or Low pressure only on the cold side. If both temperatures are weak, it’s more likely a clogged screen or valve obstruction at the fixture.
Step-by-Step What to Do
1. Turn off the shower and prepare
- Shut the shower handle to off. If you prefer extra safety, briefly shut the house shutoff before doing any work on the showerhead.
- Place a towel in the tub and lay down another towel on the wall where water may splash. Keep a small bucket or bowl handy to catch water and debris.
2. Remove and rinse the showerhead screen/restrictor
- Unscrew the showerhead: wrap a cloth around the fitting to protect the finish and use an adjustable wrench or pliers lightly, turning counterclockwise.
- Inside the head you’ll usually find a small rubber washer and a metal or plastic screen/restrictor. Remove these parts.
- Rinse the screen and restrictor under running water, use an old toothbrush to dislodge grit, and inspect for trapped particles. Soak in vinegar briefly if mineral scale is present (avoid long soaking for plastic parts).
- Reassemble the screen and reattach the head hand-tight; test the flow. If it’s still weak, continue to the next step.
3. Flush the shower valve (head off)
- With the head removed, angle the open outlet into a bucket or cover the wall and surrounding tile with towels to protect against splashes.
- Quickly open the water (start with cold or hot separately) for a few seconds to flush out loose grit. Don’t run it full blast for long — just short bursts until the water looks clear.
- Watch the stream and the bucket or cloth for particles. If you see sand or flakes, keep flushing until the output is clear.
- After flushing both hot and cold separately, reinstall the head and test both temperatures together to confirm improved pressure.
4. Inspect results
- If flow returns to normal, the screen or valve had debris and the job is done.
- If you still notice grit, persistent low flow, or the valve handle feels stiff or leaks, stop and consider professional help.
What Not to Do
- Don’t pour chemical drain cleaners into the shower to fix pressure—this is a supply-side issue; if debris flushing doesn’t help, a plumber is appropriate.
- Don’t force or pry internal valve parts without the right tools and experience — you can break the cartridge or cause leaks.
- Don’t run very hot water at full pressure while the head is off without protecting yourself from scalding and covering surfaces.
When to Call a Professional
- If flushing and cleaning the screen don’t restore normal flow.
- If the valve leaks, the handle is unusually stiff, or you find large amounts of grit that keep returning — these suggest an internal cartridge issue or a supply-line problem.
- If low pressure is throughout the house or on both shower and other fixtures, since that can indicate a main supply problem rather than the fixture.
- If you are uncomfortable disassembling fittings or protecting finishes during flushing.
Safety Notes
- Be careful with hot water — brief bursts can still cause scalding. Test temperature with a hand held at a safe distance before prolonged flushing.
- Protect tile and finished surfaces with towels when flushing the valve to avoid staining or water damage.
- Wear gloves and eye protection if you expect debris to splatter.
- Do not use power tools on chrome fittings or the valve without specific guidance — you can strip threads or shatter parts.
Common Homeowner Questions
- Why did this start right after the repair? — Disturbed sediment and scale often move when pipes are worked on or shut off and then back on.
- Will replacing the showerhead fix it? — Sometimes cleaning or replacing the head helps, but if the valve is clogged you must flush the valve first.
- How long should I flush the valve? — Short bursts of 5–10 seconds per temperature until the water runs clear; avoid long continuous runs to prevent scalding and water waste.