Quick Answer:
If a toilet refills slowly after you turn the water back on, the most common cause is trapped air or a partially closed valve in the supply line. Start by cycling the toilet shutoff (stop) valve fully closed and then fully open to clear any air pockets, then flush and watch whether the refill strength recovers after purging. If that doesn’t help, check the fill valve inside the tank and consider calling a plumber.
Why This Happens
A few simple things can make a toilet refill sluggish after a shutoff and restart:
- Air trapped in the supply line after the main was shut off. Air pockets reduce water flow until they are pushed out.
- A valve that didn’t reopen fully, either at the fixture shutoff or a nearby service valve—this restricts flow.
- Pressure-reducing valves, recent plumbing work, or debris in the line can limit supply. For situations linked to work on pressure devices, see Slow refill after PRV replacement.
- Low household demand can make the tank fill seem slower when the house is otherwise quiet—this is related to how you notice flow, similar to **Tank refills slowly when house quiet**.
Step-by-Step What to Do
Step 1 — Check other fixtures
- Turn on a nearby sink or another toilet briefly. If multiple fixtures are weak, the issue is likely upstream (main, PRV, or municipal supply).
- If only the one toilet is slow, the problem is usually local to that fixture.
Step 2 — Inspect the toilet tank components
- Remove the tank lid and peek at the fill valve and refill tube. Make sure nothing is visibly broken or stuck.
- If the fill valve has an adjustment screw, note its position but don’t force it—small adjustments can change refill speed.
Step 3 — Cycle the shutoff (stop) valve fully
- Locate the small shutoff valve on the toilet supply line. Turn it fully closed, wait a few seconds, then turn it fully open. Repeat once. This controlled cycling helps push trapped air out of the line.
- Do this slowly and deliberately—don’t use excessive force if the valve is stiff.
Step 4 — Purge and observe
- Flush the toilet to let water move through the supply line and carry air out. Observe whether the refill strength improves after purging the line.
- If flow recovers after these cycles, run the sink to confirm the line is clear. If it improves partially, repeat the controlled cycling once more.
Step 5 — If flow is still weak
- Shut off the supply, disconnect the supply hose at the base (have a bucket handy) and briefly open the shutoff to flush out debris or remaining air. Reconnect and test.
- If you’re uncomfortable disconnecting fittings, skip this and move to the next step or call a professional.
What Not to Do
- Don’t bang on valves or plumbing to “shock” trapped air out. Use controlled cycling of the valve instead.
- Don’t force a stuck valve—excessive force can break the valve or fittings and cause a leak.
- Don’t attempt major disassembly of a PRV or unfamiliar valve without the right tools and experience; if the refill doesn’t recover, a plumber is appropriate.
When to Call a Professional
- Slow refill persists after you’ve cycled the stop valve and purged the line.
- Multiple fixtures are affected or you have consistently low pressure throughout the house.
- You find a leaking or badly corroded valve, or a valve that won’t operate at all.
- You suspect a failed pressure-reducing valve, clogged supply lines, or sediment that you can’t clear safely.
Safety Notes
- Turn valves slowly to avoid water hammer and stress on fittings.
- Have towels or a bucket ready when opening supply lines or disconnecting hoses to catch water.
- If you see active leaks, corrosion, or broken parts, shut the water off at the main and call a plumber to avoid flooding.
Common Homeowner Questions
- Why did air get into the line? — Water shutoffs and pipe work trap air that needs to be purged when service is restored.
- How long should it take to recover flow? — Usually one or two controlled cycles and a flush; if it’s longer, investigate further.
- Can I fix a stuck stop valve myself? — If it’s just stiff, careful cycling can help; if it won’t turn or leaks, get a plumber to replace it.
For more related articles, see the nan hub.