Why Drains Block — and How to Clear Them

Blocked drains are among the most frequently reported household plumbing problems. Whether it's a sluggish kitchen sink, a backed-up shower, or a gurgling toilet, a blockage is usually caused by an accumulation of everyday debris. The good news is that many blockages can be resolved at home without calling a plumber.

Common Causes of Blocked Drains

  • Kitchen sinks: Grease, cooking fat, food scraps, and soap residue
  • Bathroom sinks and showers: Hair, soap scum, and toiletry products
  • Toilets: Excessive toilet paper, wet wipes (even "flushable" ones), and sanitary products
  • Outdoor drains: Leaves, soil, moss, and root intrusion

Method 1: Boiling Water (Easiest First Step)

For kitchen sinks blocked with grease or soap, pour a full kettle of just-boiled water slowly down the drain in two or three stages. This can dissolve fatty build-up and restore flow quickly. Do not use boiling water on PVC pipes — use very hot (but not boiling) water instead.

Method 2: Baking Soda and Vinegar

  1. Pour half a cup of baking soda down the drain.
  2. Follow with half a cup of white vinegar.
  3. Cover the drain and leave for 20–30 minutes.
  4. Flush with hot water.

The chemical reaction can help break down organic material. This works well for mild blockages and is a gentler, eco-friendly option.

Method 3: A Plunger

A plunger creates suction and pressure to dislodge blockages. For best results:

  • Use a cup plunger for sinks and showers; a flange plunger for toilets.
  • Ensure there's enough water in the basin to cover the plunger cup.
  • Cover any overflow holes with a damp cloth to maintain suction.
  • Plunge vigorously up and down 10–15 times, then pull away sharply.

Method 4: A Drain Snake (Plumber's Auger)

For deeper or more stubborn blockages, a hand-operated drain snake can reach further into the pipe to break up or retrieve the clog. Feed the snake in until you feel resistance, then rotate it to hook or break up the blockage. Drain snakes are available affordably at most hardware stores.

Method 5: Chemical Drain Cleaners

Commercial drain unblockers can be effective but should be used sparingly. They contain caustic chemicals that can damage older pipes and are harmful to the environment. Always follow the manufacturer's instructions, wear gloves, and never mix different chemical products.

Preventing Future Blockages

  • Fit a drain strainer or hair catcher in showers and sinks.
  • Never pour cooking oil or fat down the sink — let it cool and dispose of it in the bin.
  • Flush drains with hot water after washing up.
  • Avoid flushing anything other than toilet paper down the toilet.
  • Clean drain covers monthly to remove surface debris.

When a Plumber Is Needed

Call a professional plumber or drainage specialist if:

  • Multiple drains are blocked simultaneously (could indicate a main sewer blockage).
  • There's a foul smell coming from drains even when they're flowing.
  • You notice water backing up in unusual places (e.g., flushing the toilet causes the bath to fill).
  • DIY methods have failed after several attempts.

A plumber with a drain camera can identify exactly where and what the blockage is, making the repair faster and more accurate.