Which Is The Best Drain Unblocker On The UK Market?

Unless you live in a cave, blocked drains are a normal part of home life. For families, they can be especially frustrating.

At any time, you probably have one or two blocked or slow-running drains somewhere in the house.

A blocked drain is not difficult to fix. Some hot water or a homemade baking soda and vinegar drain cleaner quickly clears the gunk that’s clogging the drain.

But if you want to completely clear your drains and keep them that way, we highly recommend buying a drain unblocker.

This is a chemical that attacks the grease, oils, hair and whatever else is blocking the drain. It works fast and if you use it regularly, it ensures you never experience a blocked drain ever again.

Most drain unblockers are formulated to be safe for your plumbing and septic tank.

In this buying guide, we review the five best drain unblockers sold in the UK. But first, a few things to keep in mind when you are shopping for a drain cleaner.

What to Consider When Choosing a Drain Unblocker

a. Type of Cleaner

Drain cleaners come in liquid, gel, granular or powder form.

I personally prefer liquid and thick gel unblockers. They are easier to pour down the drain and they cling to the sides of the drain to ensure everything is cleared.

Liquid cleaners are generally more effective at removing clumps of hair and soap as well as deposits of oil, grease and biofilm.

b. Amount

Drain unblockers come in bottles ranging from 300ml to as much as 2L.

For large families, a bigger bottle is better. It’ll ensure you always have some on hand to clear any slow-running drain.

The right capacity also depends on your budget. A larger bottle will cost you more.

c. Preparation

I recommend getting a ready-to-use drain cleaner that doesn’t require any preparation such as diluting or mixing with anything.

You just open the cap and pour it down the drain.

This not only makes the unblocker easier to use; it also minimizes your contact with it.

Drain unblockers are typically chemicals that you don’t want to spend too much time mixing or stirring.

d. Single-Use vs. Reusable

Some drain cleaners come in small single-shot bottles. You are supposed to pour the entire bottle down the drain.

These are good if your drains don’t get clogged often.

But for families, buying a single-use drain cleaner is inconvenient and more expensive. Get a large 1-2 litre bottle instead that you can re-use.

It’s cheaper and ensures you always have some drain cleaner around. You can also unclog multiple drains at once without having to buy multiple bottles.

How to Use a Drain Unblocker

Before anything else, read the instructions on the label or leaflet. Drain cleaners are dangerous if handled improperly.

  • If there is standing water in the sink or bathroom, clear it first.
  • Carefully open the drain cleaner and pour the required amount into the drain. Make sure you follow the manufacturer instructions. With some bottles, you need to press lightly to squirt the cleaner. With others, you shouldn’t use any force at all.
  • Let the cleaner sit in the drain for the recommended amount of time. This is usually half an hour though others recommend leaving it overnight for best results.
  • Rinse the drain with hot water.

If there’s any liquid left in the bottle, store it safely away from kids.

Note: Unless explicitly instructed by the manufacturer, never mix the drain unblocker with any other chemicals such as bleach. The resulting reaction can release toxic gasses or cause burns.

Reviews of the Best Drain Unblockers

1. Mr Muscle Kitchen and Bathroom Drain Gel, 2-Pack


Mr Muscle unclogs kitchen, bathroom, bathtub and all kinds of blocked drains. The only places you can’t use it is in a blocked toilet or a sink with a waste disposal unit.

The thick heavy gel penetrates under the trapped water to reach the obstruction in the drain. For mild obstructions, 5-30 minutes is enough to unclog the drain.

If your drain is clogged thick with months or years worth of hair, soap and other gunk, leave the gel to sit overnight to sufficiently dissolve everything.

Mr Muscle Max Gel comes in two 1-litre bottles. The amount you’ll pour down the drain depends on the extent of the clogging.

Many users say they found pouring half a bottle to be enough to unclog the drain. Once the gel has done its job, the manufacturer recommends flushing the drain with hot water.

Furthermore, they recommend pouring 250ml every week in the drain to keep your pipes clear and fresh.

The 2-pack is fairly cheap so it won’t cost you much to order them every month.

What we like about it:

  • Plenty of gel – 2 litres in total.
  • Works fast.
  • Cheap but effective.

2. Buster Bathroom Plughole Unblocker


This one is a bit pricey – if you buy a single bottle – but it’s very effective at clearing hair, scale, soap and biofilm.

To save money, I recommend getting the 6-pack. Not only is the per-bottle cost way lower compared to buying a single bottle but you’ll also have a ready stock of drain cleaner to tackle drain emergencies.

This is a single-shot drain unblocker. Pour the entire 300ml gel into the drain and then give it 15-30 minutes to work.

For better results, leave the cleaner to work overnight and then flush with hot water.

Afterwards, the manufacturer recommends 100ml of the cleaner into the drain weekly to keep it from clogging.

If six bottles is too many for your needs, there are 2 and 3 pack options though they carry less savings.

What we like about it:

  • Multiple pack options.
  • Works fast and effectively.
  • Clears even the most stubborn obstructions.

3. HG Liquid Drain Unblocker, 1L


The HG Liquid unblocker not only clears stubborn clogs, it also freshens up smelly bathroom and kitchen drains.

It’s not as thick as a gel but it’s not water-thin either. It penetrates below the water without a problem and spends a lot of time on the pipe walls to dissolve whatever gunk is there.

The manufacturer says it works in a quick 30 minutes and most users agree. But you may need to leave it for an hour or longer if you have a particularly stubborn drain blockage.

It takes about 300ml or three cups to unclog a drain.

The 1L bottle is enough for several drains or multiple uses. If you want a longer lasting stock, get the 3-pack. There’s also a 1 and 2-pack available.

What we like about it:

  • Fast and effective.
  • Clears up drain smells.
  • Large 1-litre bottle.
  • Multiple pack options.

4. Scotch Corporation Liquid Instant Hair Grease Remover, 1L


This is one of the most popular drain unblockers on Amazon. It’s a bit more expensive than the others but it’s also one of the most aggressive.

It clears everything from grease and oils to hair clumps and soap scum. For hair and large bits of debris, it works by dissolving them.

For grease and oils, the chemicals in the cleaner react to generate heat that melts the oils away.

If most of the drain cleaner you’ve tried have been ineffective, I highly recommend the Scotch Corporation unblocker. It’s especially ideal for homes with long-haired family members.

Given its potency, exercise extreme caution when handling it. One customer learnt the hard way how dangerous the cleaner can be especially if it gets in the eyes.

It can cause serious eye damage and skin burns. Always wear gloves and eye protection when using it.

But it’s safe for all kinds of pipes as well as the septic tank.

The Scotch Corporation cleaner comes in around half a dozen pack options ranging from a single pack to a dozen-pack. The bigger the pack you order, the higher the savings.

What we like about it:

  • Multiple pack options to suit all kinds of homes from apartments to family houses.
  • Extremely effective against hair, grease and other obstructions.
  • Affordable (when you order a larger pack).

5. Green Gobbler Ultimate Main Drain Opener

Green Gobbler Ultimate Main Drain Opener


Get this bottle if you are looking for a large bottle of drain cleaner. It contains about 2 litres of drain unblocker, making it handy for families and large homes.

As the name suggests, the cleaner gobbles up all kinds of clogs including hair, soap, oils and grease.

Though not as powerful as the Scotch Corporation cleaner, there’s nothing the Green Gobbler won’t clear given enough time. The manufacturer recommends letting it work for 25 minutes. But you can leave it for longer if you want.

The liquid is thick like a gel so it easily clings to the walls of the pipe, dissolving and clearing everything as it goes down the drain.

What we like about it:

  • Large bottle.
  • Fast and effective.
  • Environmentally friendly and safe for your plumbing.

Frequently Asked Questions

1. How does a drain unblocker work?

Most drains are blocked and clogged by a build-up of food, grease and other icky things that find their way down your plug hole. Drain blockers come in two types – Enzyme based or chemical based.

  • Enzyme based cleaners will digest any obstruction in their way, and shouldn’t have any effect on your pipes.
  • Chemical based cleaners work by causing a reaction with whatever is causing the blockage, and will remove the obstruction by producing a gaseous heat.

Although both types of drain unblocker work well at removing the causes of a clogged up drain, the enzyme based unblocker is safer, and won’t cause any damage to your pipes. Give this one a try, or call a plumber if it doesn’t work!

2. How long to leave drain unblocker?

You should always follow the usage instructions that come with your drain cleaner. However, as a general rule, you should leave your drain unblocker to work for around 15 minutes before you flush it through with plenty of hot water.

If this doesn’t work, or only partially fixes the problem, you may have to do a repeat application straight after.

3. Where to buy a drain unblocker?

There are a huge variety of drain unblocking products you can buy, and you should be able to find a good selection at most large and small hardware shops.

Larger outlets like specialised DIY and cleaning shops will surely have what you are looking for, and you can often find them in the cleaning aisles of large supermarkets too.

If you are looking for something specific, or you can’t find what you want in a shop, then a quick browse online will definitely help you find what you are after.