Quick Answer:
After a city water outage you can get weak shower flow because debris or air entered the pipes. Start by removing the showerhead and flushing the branch into a bucket, then check aerators and other fixtures for blockages. If flushing and cleaning don’t help, call a plumber.
Why This Happens
When the main water supply is shut off and then turned back on, loosened scale, sand, and small bits of pipe lining can travel through the system. Those particles often collect at the narrow openings of showerheads, faucets, and aerators, reducing flow. Air pockets can also temporarily reduce pressure or cause sputtering.
If you recently did seasonal work or remodeling, the problem can be similar — deposits or trapped air. For more on related causes check Shower pressure worse after winterization and Shower pressure low after remodel.
Step-by-Step What to Do
1. Turn off the shower and isolate the outlet
- Turn the shower valve fully off. If you have a shutoff for the bathroom or the shower mixing valve, use it to avoid running water through the whole house.
2. Remove the showerhead and inspect
- Unscrew the showerhead. Check for visible debris, mineral build-up, or damaged seals.
- If there’s visible sediment, gently brush it away with an old toothbrush or soak the head in vinegar to loosen mineral deposits.
3. Flush the shower line into a bucket
- Point the open shower arm into a bucket and briefly open the valve to flush water and any debris out of the branch line. Run until the water runs clear (a few seconds to a minute).
- Take care with hot water — test water temperature before flushing to avoid scalding.
4. Re-test flow without the head, then with the head
- With the showerhead removed, check the raw flow at the arm. If strong, the head is the likely restriction. If still weak, the issue may be upstream.
- Clean or replace the showerhead before re-installing and test again.
5. Check aerators and other fixtures for debris
- Remove faucet aerators and check screens for grit or sediment. Flush those lines briefly as well — debris can affect other fixtures.
- Work from the closest fixtures outward so you can spot where the flow returns to normal.
6. Optional simple filter check
- If you have whole-house or point-of-use filters, check their housings for trapped sediment and change filters if they’re clogged.
What Not to Do
- Don’t ignore debris after outages — trapped particles can damage fittings and build up over time.
- Don’t force or hammer fittings to “clear” a blockage; that risks breaking pipes or valves.
- If flushing and cleaning the showerhead and aerators don’t restore pressure, a plumber is appropriate — don’t keep running water hoping it will fix itself.
When to Call a Professional
- Low pressure persists after flushing and cleaning the showerhead and aerators.
- Multiple fixtures in the house show reduced pressure (possible mains issue or closed valve at the meter).
- Water is discolored after flushing, or you see continuous sand-like particles; a plumber can check supply lines, the pressure regulator, and filters safely.
- You suspect damage to valves or the water heater, or if you’re unsure how to safely isolate or test parts of the system.
Safety Notes
- Be careful of hot water when flushing lines — open the valve slowly and test temperature before placing your hands under the flow.
- Wear gloves if handling debris or corroded parts.
- If you need to shut off the main water, know where the main shutoff is and how to operate it. If you’re uncomfortable, call a professional.
Common Homeowner Questions
- Why did this start right after the outage? Debris and air move through pipes when supply is restored, which can lodge in narrow openings and reduce flow.
- Will the pressure improve on its own? Minor air often clears quickly, but sediment usually needs to be flushed or removed from fixtures to restore normal flow.
- Can I replace the showerhead myself? Yes — most heads screw off by hand or with a wrench and are simple to clean or replace.