Quick answer
If only one fixture is slow, the clog is usually in that fixture's drain. If several drains back up together — especially a tub or floor drain when you flush — the blockage is likely in the main line and needs professional cleaning.
One fixture vs. the whole house
- One sink slow, others fine: fixture or branch clog
- Toilet gurgles when the tub drains: shared line or vent issue
- Tub fills when the toilet flushes: main line blockage
- Backups after heavy rain: possible sewer line problem
What's safe to try
A plunger on a single fixture or cleaning a sink's stopper and trap. Skip chemical cleaners — they rarely fix deep clogs and can harm older pipes. If it doesn't clear quickly, call for drain cleaning.
Prevention
- Keep grease out of the kitchen sink
- Never flush wipes, even "flushable" ones
- Use hair catchers in showers
- Address hard water scale
Common questions
How often should drains be cleaned?
There's no fixed schedule. If you have recurring clogs, a professional cleaning and a look at the cause is better than repeated quick fixes.