5 Drain Unblocker Products Tested: Which Actually Work?

When a drain starts running slowly, most people reach for a bottle of drain unblocker from the supermarket before calling a professional. But do these products actually work? We tested five of the most popular UK drain unblocker products to find out.

Note: For serious or recurring blockages, chemical drain cleaners are rarely sufficient. They work best on minor, slow-draining issues. For anything more severe, find a professional drain engineer near you.

1. Mr Muscle Drain Foamer

Price: ~£5 from most supermarkets
How it works: Foaming action that expands to fill the pipe
Our verdict: Effective on light grease and soap build-up. The foaming action means it contacts the pipe walls rather than just sinking to the bottom. Took about 30 minutes to work on a slow-draining bathroom sink. Won't shift a serious blockage, but good for maintenance.

Rating: 4/5 for minor blockages

2. Buster Bathroom Plughole Unblocker

Price: ~£3.50
How it works: Caustic soda formula designed for hair and soap
Our verdict: Specifically designed for bathroom drains, and it shows. Dissolved a hair-and-soap blockage in a shower drain within 20 minutes. Less effective on kitchen drains with fat build-up. Good value for money.

Rating: 4/5 for bathroom drains

3. HG Kitchen Drain Unblocker

Price: ~£7 from hardware stores and Screwfix
How it works: Powerful alkaline formula for fat and food
Our verdict: The most effective product on kitchen drain blockages in our test. Cleared a heavily greased kitchen drain in about 45 minutes. More expensive but genuinely works on tougher kitchen blockages. The Dutch brand has a strong following among plumbers.

Rating: 4.5/5 for kitchen drains

4. Domestos Sink & Drain Unblocker

Price: ~£3
How it works: Bleach-based thick liquid formula
Our verdict: Readily available but underwhelming results. Improved flow slightly on a slow drain but didn't fully clear the blockage. Better used as a maintenance product (monthly pour) than a cure for existing problems.

Rating: 2.5/5

5. Bicarbonate of soda + white vinegar (DIY method)

Price: ~£1
How it works: Pour half a cup of bicarb down the drain, follow with a cup of white vinegar, leave for 30 minutes, flush with boiling water
Our verdict: The classic home remedy. Produces a satisfying fizz but the reality is that the chemical reaction is too weak to dissolve serious blockages. Works well as a deodoriser and for very minor slow drains. The Which? drain unblocker guide comes to a similar conclusion.

Rating: 2/5 for actual blockages

The bottom line

Supermarket drain unblockers can help with minor, slow-draining issues — particularly HG for kitchen drains and Buster for bathroom drains. But for a proper blockage where water won't drain at all, or for recurring problems, you need a professional with a high-pressure water jetter. A typical drain clearance costs £100–£250 and most companies offer a same-day service.

Important safety note: Never mix different drain cleaning products — they can produce toxic fumes. Always wear gloves, avoid skin contact, and follow the instructions on the bottle. If in doubt, call a professional.