Why does my toilet keep running after it fills?
A worn flapper, incorrect float level, caught chain, or fill valve is usually allowing tank water to keep moving.
Urgency: low
What this means
Inspect the accessible tank parts after closing the toilet shutoff without forcing it.
Safe checks
- Close the shutoff
- remove the tank lid carefully
- check chain slack and whether water reaches the overflow tube.
Stop and get help if
- Stop if the shutoff leaks, is seized, or water is escaping onto the floor.
Which professional to call
Contact the matched licensed or qualified trade if safe checks do not resolve the issue.
Find the relevant tradeSource and method
This answer combines HomeSOS's structured triage with safety boundaries supported by a public source. It does not replace inspection.
Health Canada: Home safety and indoor air guidanceReviewed August 12, 2026