Unblock a Kitchen Sink — Trade Methods That Work
A blocked kitchen sink is nearly always caused by fat and food debris. Chemical unblockers dissolve fats but not solids, and they corrode chrome and rubber over time. Here is the trade method — cheap, fast and non-destructive.
Step-by-step method
1. Confirm the blockage location
Fill and release — if the kitchen sink alone is slow, the blockage is local (trap or branch). If multiple fixtures back up, the problem is downstream at the stack or drain.
2. Try mechanical clearance
To clear a kitchen sink, use a plunger; if that fails, remove the trap under the sink and clear by hand. Repeat 6–8 strong plunge cycles maintaining a seal — a partial vacuum is what shifts the mass.
3. Enzyme unblocker overnight
If flow is restored but slow, pour 500ml bio-enzyme drain treatment (Bio-Clean or Ecozyme) at bedtime. Do NOT use caustic soda on plastic waste pipes — it warps solvent-weld joints.
4. Lift the trap for stubborn blocks
Bucket underneath, unscrew the trap by hand (never a wrench — plastic threads strip). Empty, brush clean, refit with fresh trap washer if the old one is compressed.
5. Rod from the manhole
If the local branch is clear but water backs up, the blockage is in the drain run. Lift the nearest manhole, rod downstream toward the main sewer with a plunger head first.
Frequently asked questions
Will bleach unblock a kitchen sink?+
No — bleach disinfects but does not dissolve fat, hair or paper. Use enzyme unblocker or mechanical clearance.
How do I stop the kitchen sink blocking again?+
Fit a strainer, dispose of fat in the bin (not down the drain), and run enzyme unblocker monthly.
When should I call a drainage engineer?+
Waste backing up into multiple fixtures, sewage smell, or repeated blockages within 30 days — likely a main-drain issue needing CCTV survey.