Best kitchen drain unblockers

We put kitchen drain unblockers from popular brands including Cillit Bang, Domestos and Mr Muscle to the test on a U-bend blocked up tight with stubborn food residue and grease. 

We also tested the home remedy of bicarbonate soda, salt and vinegar to see how it compared. 

The products below are suitable for food blockages. If you want to unblock a drain clogged with hair, take a look at our pick of the best shower drain unblockers.

As with any bleach-based products, make sure you always wear gloves, old clothes and follow the instructions carefully. 

The best kitchen drain unblockers from our test

Compare our results and prices at a glance in our table below, or read on for our full reviews.

Best Buy: Mr Muscle Power Gel Drain Unblocker

Available from Asda (£3) Ocado (£3.75) Sainsbury's (£3.90) Waitrose (£3.95)  Tesco (£4) Amazon (£5.40 x2)

Pros

• Clears the pipes
• Works within five minutes

Cons

• In the smaller size it's a single-use plastic bottle

Our verdict Simple to use, effective and fast-acting

Size 500ml, also comes in 1 litre

Suitable for a septic tank Yes

All the drain unblockers tested worked (although, some needed a bit of extra help as we explain), but Mr Muscle Power Gel was easily the fastest. 

Within five minutes the clogs in our drains were dissolved. 

If getting the job done fast is what's important to you, then have a bottle of this waiting under your sink. 

See how it fared in our best shower drain unblocker tests.

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 Domestos 15 Minute Sink & Pipe Unblocker Gel

Available from Ocado (out of stock) also available at Amazon (out of stock)

Pros

• Clears the pipes
• Works within 15 minutes

Cons

• Single-use bottle
• Very small printed instructions on bottle

Our verdict Fast-acting unblocker

Size 500ml

Suitable for a septic tank Yes

You won't be disappointed with this if you need to unblock your sink. 

Although the printed instructions are very small, it's an easy to use product.

See our pick of the best kitchen clening sprays, best bathroom cleaning sprays,  best all-purpose cleaning sprays and best oven cleaners, tried and tested by our experts.

Sainsbury's Sink & Plughole Unblocker

Available from Sainsbury's (£2.25)

Pros

• Clears the pipes
• Works within 15 minutes

Cons

• Single-use bottle

Our verdict Good results with a quick turnaround

Size 500ml

Suitable for a septic tank Yes

It only took 15 minutes for this plughole unblocker from Sainsbury's to cut through the grease and food residue. 

Once it had finished, the pipes and U-bend were squeaky clean.

Essential Waitrose & Partners Drain Unblocker

Available from Waitrose (£2.45)

Pros

• Clears the pipes
• Works within 15 minutes

Cons

• Single-use plastic bottle

Our verdict Fast-acting unblocker with consistent results

Size 500ml

Suitable for a septic tank No

Like many of the other bleach-based products, this unblocker from Waitrose & Partners worked quickly to get rid of the clog. 

Cillit Bang Drain Odour Eliminator & Unblocker Gel

Available from Ocado Asda (£5.15)

Pros

• Clears the pipes

Cons

• Single-use bottle

Our verdict Effective and affordable

Size 500ml

Suitable for a septic tank The manufacturer says they are unable to test on all septic tanks. Therefore, it's safest for you to check with your septic tank provider. 

This unblocker gel from Cilit Bang was not the fastest, but it was by no means the slowest product from our investigation. 

It effectively removed the clogs in both of our tests.

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Soda Crystals 

Available from Tesco Asda Ocado Sainsburys (£2) Morrisons (£2.35)

Pros

• Clears the pipes
• Offers lots of cleaning options

Cons

• Requires more preparation than the others

Our verdict Effective but difficult to prepare

Size 1kg

Suitable for a septic tank Yes

Soda Crystals worked, but it's a faff to get ready, especially compared with the other products we tested. 

You need to prepare the solution first, then pour it down the drain. On both occasions when we tested it, the blockage was removed within 30 minutes.

Soda Crystals is an incredibly affordable product with a lot of cleaning utility as you can use it to clean your washing machine, barbeque, pots and pans, as well as stain removal on clothes and fabrics.

Ocado Sink & Drain Unblocker Gel

Available from Ocado (£2.25)

Pros

• Clears the pipes

Cons

• Can take up to three hours to work
• Single-use plastic bottle

Our verdict Not the fastest, but by no means less effective

Size 500ml

Suitable for a septic tank Yes

Although it took three hours both times we tested it, this Ocado Sink & Drain Unblocker Gel proved just as effective as most of the others from our test. 

HG Kitchen Drain Unblocker

Available from Tesco (£4.50) also available at B&Q (£6.50) Robert Dyas (£9) Amazon (£15)

Pros

• Clears the pipes

Cons

• Can take up to six hours to work
• No child safety cap (although it's not required by law to have one)

Our verdict Slower than most but effective

Size 1 litre

Suitable for a septic tank Yes

You get more for your money, but this product isn't as simple as just pouring and leaving as you need to mix it with water.

It does take a minimum of six hours to work, but if you're happy to wait or leave overnight, this could be the one for you. 

Ecozone Kitchen Drain Unblocker

Available from Ecozone Direct (£7.69)

Pros

• Clears the pipes
• Doesn't have too strong a scent

Cons

• Can take up to 12 hours to work
• No child safety cap (although it's not required by law to have one)

Our verdict Does the job but slowly

Size 1 litre

Suitable for a septic tank Yes

During our tests, the Ecozone Kitchen Drain Unblocker did work to remove the clog from our pipes but it took a very long time. 

For most people, this won't be an issue if you make sure you do it in the evening before you go to bed. 

Tesco Sink & Drain Unblocker

Available from Tesco (£2)

Pros

• Clears the pipes
• Works within 15 minutes

Cons

• Single-use plastic bottle

Our verdict A speedy solution to a blocked drain

Size 500ml

Suitable for a septic tank Waiting for a response from the manufacturer

After 15 minutes, the Tesco Sink & Drain Unblocker had done its job and removed the clog from our U-bend.

Buster Kitchen Plughole Unblocker

Available from Ocado (£3) Waitrose (£4.30) Robert Dyas(£6.69) Amazon

Pros

• Doesn't leave a lingering scent

Cons

• We needed a plunger to completely remove the blockage
• Single-use plastic bottle

Our verdict Left behind a new blockage

Size 200g

Suitable for a septic tank Yes

This product did remove the clog, but the mass of the granules created a new blockage we had to force out with a plunger.

In both of our tests, Buster Kitchen Plughole Unblocker dissolved the clogs into a greasy acidic sludge, but the weight and mass of leftover granules fused together to form a new blockage. 

However, this second clog was easily flushed away with a single strike of our plunger. 

When you use this product don't leave it in the pipes for more than 20 minutes, make sure you wear gloves, don't get any on your skin and open all the windows in the room. 

How we tested kitchen drain unblockers

We selected one drain unblocker per brand, looking at liquid or pouring products widely available in national retailers and purchased all the products we tested.

To find out which of our selected drain unblockers was the best, we put the whole selection through the following tests. 

The setup

• Using a freestanding catering sink, we got one 44mm U-bend per test and stuffed it with a clog made from equal parts grated broccoli, melted lard and breadcrumbs, which we then allowed to harden for 12 hours. 

• To ensure each clog was firmly lodged in place, 500ml of boiling water was poured into the plughole before the tests began. 

• The unblockers were then applied following their instructions and left for the minimum required time. 

• Afterwards, the U-bends were flushed through with eight litres of hot tap water. If necessary, a plunger was used at this point. We've noted above when a plunger was needed. 

The test

• The pipes were examined with a tube camera before and after the products were applied to see how effectively they worked. 

• Then we timed how long it took for eight litres of cold tap water to pass through the U-bend and pipes. 

• We compared these timings to a test done on an unused U-bend. The quicker the water passed through the better, the unblocker had worked. Each product was tested twice. 

How to unblock a kitchen drain

• When working with bleach it's advisable to wear gloves and long sleeve clothing, but make sure it's something that you don't mind risking getting bleach on. 
• Pour around 500ml of hot tap water into the drain and allow it time to flow down. If it gets stuck, use a plunger to force it down. 
• Then add your kitchen drain unblocker of choice and leave it to work for the recommended time.
• Finally, pour another 500ml of hot water into the drain once the unblocker has had enough time.

Drain unblocker home remedy: bicarbonate soda, salt and vinegar

Did this home remedy get rid of the greasy food residue clogs in our tests? In short, no. 

In both attempts, the mixture of bicarbonate soda (125g), salt (125g) and vinegar (125ml) seemed to do nothing but fizz and spit in the plughole. 

After waiting 10 minutes, the clog was still firmly in place and so a lot of rigorous plunging action was required to dislodge it. 

However, this home remedy is good for regular drain maintenance to prevent major blockages. 

How to prevent kitchen drain blockages

Most of the time serious blockages in drains are preventable. Here are some simple steps to help prevent a dreaded blocked sink: 

• Scrape plates Make sure you remove food residue from your plates, bowls and utensils before you put them in the sink.
• Drain protector Get a drain protector to catch stray bits of food residue before they disappear down the plughole.
• Enzyme cleaning sticks Dropping an enzyme cleaning stick down the plughole once a month is a good way to prevent germs, odours and blockages. 
• No coffee grounds in the sink Throw away your coffee grounds in your food waste, compost or bin.
• Collect the fat Collect fat and grease from cooking in a disposable container (juice or milk carton or another non-recyclable container) before putting it in with your general waste.

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What are the chemical hazard symbols and what do they mean?

Many drain unblockers contain chemicals that are hazardous to us and the environment. 

Below you can see the symbols found on some products, what they mean and the safety advice for handling them. 

Chemical hazard symbols and what they mean
	Explosive (symbol: exploding bomb)
	A substance that under defined test conditions when dry or under the effect of flame or heat may explode. Read and use instructions for the given material. Ensure containers are stored in a cool, well-ventilated place with tight-fitting lids. Store away from sources of heat and ignition.  Ensure the material and its containers are disposed of in a safe manner.
	Flammable (symbol: flame)
	Flammable if exposed to ignition sources, sparks or heat. Some substances with this symbol may give off flammable gases in contact with water.  Avoid ignition sources (sparks, flames and heat).  Keep your distance.  Wear protective clothing.
	Oxidising (symbol: flame over circle)
	May cause explosion, fire or damage to living tissue resulting in chemical burns. Reacts with other substances to produce a highly exothermic reaction. Read and use instructions for the given material.  Ensure containers are stored in a cool, well-ventilated place with tight-fitting lids.  Store away from sources of heat and ignition.  Ensure the material and its container are disposed of in a safe manner.
	Corrosive (symbol: corrosion)

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