Quick Answer:
If the tank is taking much longer than usual to refill after a flush, first check the tank internals. Lift the lid and confirm the fill valve is delivering a strong stream of water into the overflow tube. If the stream is weak, inspect the inlet screen and the shutoff valve for debris or partial closure before replacing parts.
Why This Happens
- Partial shutoff valve: the supply valve under the tank may not be fully open or is clogged with mineral deposits.
- Restricted inlet screen: debris or mineral buildup on the supply inlet screen reduces flow into the fill valve.
- Faulty fill valve or float: worn or faulty parts let less water through or stop the valve early.
- House water pressure issues: low pressure from the main or a pressure-reducing valve can slow the refill.
- Supply line blockage: internal sediment in old pipes or a kinked flexible supply line can limit flow.
Step-by-Step What to Do
1. Observe the refill
- Lift the tank lid and place it somewhere safe. Watch the fill valve as the tank refills.
- You should see a steady, strong stream into the overflow tube or into the tank fill area. If the stream is thin or sputtering, note that.
2. Check the toilet shutoff valve
- Locate the shutoff valve on the supply line beneath the tank. Turn it fully counterclockwise to open.
- If it was partially closed, opening it often restores normal refill speed.
3. Inspect the inlet screen
- Shut off the supply at the shutoff valve. Disconnect the supply line from the fill valve (have a towel ready).
- Look for a small mesh screen or washer at the valve inlet. Rinse away sediment and debris, then reconnect and test.
- If cleaning the screen restores flow, that was the problem.
4. Test home water pressure and other fixtures
- Run a nearby faucet while watching the toilet refill speed. If both are slow, the issue may be house pressure.
- Check for work on the supply main or a pressure-reducing valve that might be limiting flow.
5. Adjust or replace the fill valve
- If the supply and screen are clear but flow is still weak, the fill valve may be worn. Many fill valves are inexpensive and easy to replace.
- Follow manufacturer steps for replacement or call a plumber if you’re unsure.
6. Look for patterns
- If the slow refill began after recent plumbing work, or only happens at certain times, note that for troubleshooting or for a professional. For example, see Slow refill after plumbing repair and Slow refill only at night for possible causes.
What Not to Do
- Don’t assume slow refill is normal aging—restricted flow wastes time and water.
- If you can’t identify the cause, a plumber is appropriate.
- Don’t force or overtighten plastic fittings; that can crack components and cause leaks.
When to Call a Professional
- If cleaning the inlet screen and opening the shutoff valve don’t fix the problem.
- When multiple fixtures have low pressure or you suspect a hidden blockage in supply piping.
- If you find leaks, cracked tank parts, or are not comfortable replacing the fill valve yourself.
Safety Notes
- Turn off the toilet shutoff valve before disconnecting the supply line to avoid flooding.
- Use a towel or small container to catch water when disconnecting lines.
- Wear gloves if working with mineral deposits and be gentle with plastic parts to avoid breaking them.
Common Homeowner Questions
- Why did this start suddenly? A sudden change often points to a partially closed valve, debris dislodged into the inlet, or recent plumbing work.
- Can I fix it myself? Often yes—cleaning the inlet screen or replacing a fill valve are common DIY tasks if you’re comfortable with basic tools.
- Will slow refill increase my water bill? Yes—longer refill times mean the toilet runs longer and can waste water, so it’s worth fixing promptly.
For more related articles, see the nan hub.