Quick Answer:
If one shower that was fine yesterday has low pressure today, first compare it to another shower or fixture in the house. If only that shower is affected, remove and inspect the showerhead and arm for mineral buildup or a partially closed shutoff. If several fixtures are weaker, check main pressure, the water meter shutoff, and faucet aerators. If the problem is house‑wide or you find no simple clog, call a plumber.
Why This Happens
- Mineral deposits or debris can clog a single showerhead or the arm overnight.
- Valves can become partially closed after maintenance, accidental bumps, or freeze protection actions.
- A problem at the meter, a leaking pipe, or a failing pressure regulator can reduce pressure to multiple fixtures.
- Water heater or hot‑side supply issues cause low pressure only on the hot side.
Step-by-Step What to Do
1. Compare to another shower or fixture
- Turn on a second shower or a sink on the same floor and note pressure. This tells you whether the issue is local or whole‑house.
2. If only one shower is weak, inspect the head and arm
- Remove the showerhead and look for mineral buildup or visible debris in the screen or cartridge area.
- Unscrew the shower arm and check the pipe opening for blockages. Clear gently with a brush or a bit of vinegar soak if needed.
- Reinstall the head and test. A clogged head often restores pressure when cleaned or replaced.
3. If multiple fixtures are affected, check main pressure and aerators
- Check nearby sink aerators and the showerhead screens—debris can affect several fixtures at once.
- Confirm the main shutoff at the meter or the house valve is fully open.
- If you have a pressure‑reducing valve, its failure can reduce pressure to the whole house; a plumber should inspect that.
4. Is it hot, cold, or both?
- Test hot and cold separately. If only hot is weak, the issue may be at the water heater, mixing valve, or the hot‑side supply. See the related guidance on Low pressure only on hot side at shower.
5. Check for recent work or changes
- If you just had plumbing service, parts may have been left partially closed or disturbed. That can cause sudden drops—see the note about Shower low pressure after plumbing repair.
6. Record what you find and act accordingly
- If cleaning the head fixes it, consider a replacement head with anti‑clog features to avoid repeats.
- If the issue is beyond simple cleaning or multiple fixtures are affected, contact a licensed plumber.
What Not to Do
- Don’t keep swapping fixtures blindly—first verify whether the problem is local or whole‑house. Randomly replacing parts wastes time and money.
- Don’t force fittings or overtighten connections; that can damage threads and cause leaks.
- If multiple fixtures changed at once, don’t assume a single shower part is the cause—call a plumber to diagnose the system‑level issue.
When to Call a Professional
- Pressure is low at multiple fixtures across the house.
- You cannot clear an obvious clog in the head or arm, or the cartridge looks damaged.
- There are signs of leaks, banging pipes, or a sudden change after municipal work or repairs.
- Your main shutoff or pressure‑reducing valve needs adjustment or replacement.
Safety Notes
- Turn off the local shutoff before removing a showerhead to avoid sudden water flow.
- Don’t use harsh mechanical force on brass or chrome fittings—use the proper wrench and a cloth to protect finishes.
- If you smell gas, see electrical issues, or find significant water leaks, stop and call the appropriate emergency service or plumber immediately.
Common Homeowner Questions
- Why did pressure drop overnight? Rapid drops are usually from a sudden clog, a partially closed valve, or recent work that altered a valve position.
- Can I fix low pressure myself? Yes, if it’s a single showerhead or an aerator clog—cleaning or replacing the head often fixes it; system problems need a pro.
- Will mineral buildup come back? It can. Consider a rinseable head, a filtered inlet, or routine cleaning if your water is hard.