Symptoms
- Water goes down slowly instead of all at once
- Sometimes clears fully after a minute or two
- No overflow, just a sluggish drain
- Been getting slower over days or weeks
Likely causes
- CommonPartial clog forming in the trapPaper or waste has narrowed the passage without fully blocking it yet.
- CommonWeak flush volumeNot enough water is released to move waste efficiently, so it drains gradually instead.
- PossibleMineral buildup narrowing the trap or jetsHard water scale reduces the effective size of the passageway over time.
- PossibleVenting issue reducing siphon strengthLimited air flow behind the water slows how fast it can be pulled through.
What to do
- Run a toilet auger through the trap now, before it becomes a full clog.
- Check and adjust the tank water level if it's on the low side.
- Inspect and clean rim holes and the siphon jet for mineral buildup.
- Try a hot water and dish soap pour (a few cups) to help lubricate and loosen a partial clog, letting it sit 10 minutes first.
- Watch for gurgling from other fixtures at the same time, which points to a venting issue instead.
- Note how the drain speed changes after each attempted fix.
Tools and parts
- Toilet auger
- Dish soap
When to call a pro
Call a plumber if the slow drain persists after augering and cleaning, since it may point to a line issue further down.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.