Quick Answer:
Most often a slow refill right after work means debris or a partially closed stop valve is restricting flow. Briefly closing and reopening the toilet stop valve to flush the line, then checking the fill valve screen and retesting the refill speed will fix the issue in many cases.
Why This Happens
When a plumber or you work on supply lines, pipes, or the main shutoff, small bits of mineral scale, sand, rust, or plumber’s debris can get dislodged. Those particles can lodge in the shutoff valve, the fill valve inlet, or the tiny screen inside the fill assembly and reduce flow. A valve not fully opened after the job can also limit water speed. Similar troubleshooting tips apply in other situations, for example **Slow refill only at night** and **Toilet fills slow after city outage**.
Step-by-Step What to Do
1. Time the refill
- Flush the toilet normally and use a stopwatch or watch to time how long the tank takes to reach the normal fill level. Note the time so you can compare after each step.
2. Check the shutoff (stop) valve
- Locate the small valve on the water supply line under or behind the tank.
- Briefly close the valve fully, wait one to two seconds, then reopen it fully. This often flushes small debris out of the line and clears a partially open valve after repairs.
- Flush and time the refill again.
3. Inspect the fill valve screen
- Turn off the shutoff valve and flush to empty most of the tank.
- Remove the supply hose at the bottom of the fill valve if your model has a removable nut (have a small bucket or towel ready for water). Many fill valves have a small screen where the supply connects; gently clean any visible debris with a soft brush or rinse under clean water.
- Reattach the hose, turn the shutoff back on, and flush to retest refill speed.
4. Check the fill valve operation
- With the tank open, watch the fill valve while it runs. If flow is weak at the valve inlet but the shutoff is fully open and the screen is clean, the fill valve may be partially clogged or failing.
- If needed, replace the fill valve following the manufacturer’s instructions or call a pro.
5. Confirm normal performance
- If refill speed returns to normal after cleaning or flushing the valve, run a couple more tests to be sure the fix is consistent.
- If flow stays slow, note whether other fixtures are also affected—this helps diagnose a broader pressure or supply issue.
What Not to Do
- Don’t ignore slow refill after repairs—debris is common and can worsen or clog other parts.
- Don’t force or hammer valves, and don’t overtighten connections; that can damage fittings.
- Don’t use strong chemical drain cleaners in the tank; they can damage parts and won’t clear supply-line debris.
- If screens won’t clear or you can’t access the inlet safely, a plumber is appropriate instead of attempting risky repairs yourself.
When to Call a Professional
- Slow refill persists after you’ve flushed the stop valve and cleaned the fill screen.
- Other fixtures show reduced pressure, indicating a larger supply or pressure problem.
- You suspect damage to the shutoff valve, the fill valve, or there is a leak you can’t safely fix.
Safety Notes
- Turn off the shutoff valve before disconnecting supply fittings. Have towels or a small bucket to catch water.
- Work gently with plastic parts—many are brittle with age and can crack if forced.
- If you smell gas or see major leaks, stop and call a professional immediately.
Common Homeowner Questions
- Why is the refill slow only after the plumber leaves? Small debris disturbed during the repair is the usual cause; flushing the shutoff often clears it.
- Will a new fill valve fix the problem? Yes if the valve itself is clogged or failing; try cleaning the screen first before replacing it.
- Can I keep using the toilet if refill is slow? You can use it, but don’t ignore the issue—continued debris can cause bigger clogs or damage over time.