Why Is My Drain Slow? A Diagnosis Guide
A single lazy drain points to a clog close by; a whole house of them points to the main.
- Step-by-step, written from real jobs
- Tools to have ready and safe stopping points
- Where to stop and hand it to a licensed plumber

- Licensed plumbing trade
- Camera before digging
- Written job notes
- Phone-only booking
Summary card
A single lazy drain points to a clog close by; a whole house of them points to the main.
A slow bathroom sink is usually hair and soap in the trap or pop-up stopper. A slow kitchen sink is usually grease. A slow tub is usually hair.
A toilet that burbles as the basin empties, or a basement grate that overflows, means the clog lives deeper in the system.
The procedure
- Note which fixtures are slow
- Clean the stopper and trap of a single slow sink
- Plunge with a cup plunger
- Check for gurgling in other fixtures
- Avoid chemical cleaners
Tools to have at hand
- Plunger
- Plastic hair snake
- Bucket
Do it in this order
- 01
Check if one drain or several are slow
- 02
For one sink, pull the stopper and clean the hair
- 03
Use a plunger with the overflow covered
- 04
Try a plastic snake in the drain
- 05
If several drains are slow, it may be the main
Two slow fixtures at once points past the traps to a shared branch or the main.
Whitby Plumbing, from the job
Stop and phone a plumber if
- Sinks, tub and toilet are all sluggish
- Water rises out of the basement drain
- Plunging and snaking do not work
Notes for Whitby
Older Whitby homes with cast-iron drains often see slow drains from internal scale.
When the desk should take over
Phone once two fixtures are slow at the same time or the basement grate overflows.