Best drain unblocker: Unclog your sinks with the best chemical and enzyme-based unblockers
Shower, bath and kitchen sink clogged to a standstill? Get those plugholes flowing fast again with the best drain unblockers
It doesn’t take long for hair, food waste, soap scum and a dollop of unidentifiable household gunk to clog up your plugholes. The best drain unblockers can go where no plunger or kettle of boiling water can, dissolving and even digesting the clogs without damaging you, your sink or your plumbing.
Drain unblockers are surprisingly varied products. Some are designed specially to tackle bath and shower wastes clogged to a standstill with hair and grease, while others use gentler enzyme-based formulas to eat away mould and grime from outdoor drains and waste disposal units. The best unblockers cling to the walls of your pipes and keep them flowing freely for months to come.
Read on to discover our top recommended drain unblockers to free various pipes around your home, or skip to our buying guide for more tips on choosing the right unblocker for the job.
Best drain unblockers: At a glance
| Best for hair-clogged baths and showers | Buster Bathroom Plughole Unblocker | £4.75 | Check price at Amazon |
| Best for removing stubborn blockages | Instant Power Hair & Grease Drain Opener | £15 | Check price at B&Q |
| Best for outdoor drains | Jeyes Drain Unblocker Heavy Duty | £6.41 | Check price at Amazon |
The best drain unblockers you can buy
1. Buster Bathroom Plughole Unblocker: Best drain unblocker for hair-clogged baths and showers
Price when reviewed: £4.75 (300ml) | Check price at Amazon
You don’t see Amazon reviews much more positive than those for Buster Bathroom Plughole Unblocker. There are hundreds of five-star reviews from verified buyers who’ve spent years pulling sludge from slow-draining showers and plugholes – and even dismantling wastes regularly to remove human hairballs – only to find that Buster does the job faster, without corroding pipes or sinks.
This relatively small 300ml ‘one-shot’ bottle is enough to get a clogged pipe flowing freely again. As with all these products, leaving it overnight before a thorough rinse with hot water produces the best results, but buyers report that Buster can get a fully-clogged shower waste pipe flowing freely in less than an hour. It also lacks the bleachy smell of Mr Muscle, making it more pleasant for the bathroom.
Key details – Size: 300ml; Type: Chemical; Format: Liquid
2. HG Kitchen Drain Unblocker: Best enzyme-based drain unblocker
Price when reviewed: £8.70 (1l) | Check price at Amazon
This affordable, biodegradable liquid unblocker from Dutch cleaning specialist HG uses enzymes and microbes to tackle grease and food particles in the waste pipes under your kitchen sink and keep those plugholes emptying fast. It’s not quite strong enough to eat through solid blockages (you’ll need a plunger, plumber or chemical unblocker for that), but it’s brilliant for cleaning gunky pipes before they can get fully clogged, and for keeping the kitchen smelling clean. And its enzyme-based formula means it’s safer to keep around the house and use on pipes long-term, although it should still be kept out of reach of kids and pets.
Key details – Size: 1l; Type: Enzymatic; Format: Liquid
3. Instant Power Hair & Grease Drain Opener: Best drain unblocker for removing stubborn blockages
Price when reviewed: £15 (1l) | Check price at B&Q
Big red capital letters on a black bottle – this stuff means business, right? Very much so. This drain unblocker from Texas-based chemical company Scotch Corporation claims to be the strongest formulation on the market. It also claims to be safe for ‘all’ types of pipe, but the label carries the disarming instruction: ‘Wear safety goggles to protect from possible eruption of Lye’. That’s caustic soda to you and me.
The thin liquid consistency makes splashes a real risk, so take extremely good care when using this stuff. The strong chemical formula melts away all kinds of blockage, including solidified grease and oil, although you may need to leave it overnight to tackle large blockages. And like other chemical unblockers, it’s not safe to use in toilets or waste disposals.
Key details – Size: 1l; Type: Chemical; Format: Liquid
4. Jeyes Drain Unblocker Heavy Duty: Best unblocker for outdoor drains
Price when reviewed: £6.41 (1l) | Check price at Amazon
Specially formulated for use outdoors, this thick liquid from Jeyes is strong enough to open fully blocked outdoor drains that have been clogged to a standstill with leaves and household waste. It deodorises while it works, leaving drains smelling pleasantly fresh, and the clingy consistency means it keeps drains unblocked for weeks on end.
Despite its outdoor-friendliness, it’s still a caustic chemical formula, so be wary of using Jeyes in places where it might be accessed by pets and wildlife, and flush with hot water when the blockage has cleared.
Key details – Size: 1l; Type: Chemical; Format: Liquid
5. Instant Power Slow Drain Build-Up Remover: Best enzyme-based drain unblocker for toilets and waste disposals
Price when reviewed: £21 (1l) | Check price at Amazon
Unlike chemical-based drain unblockers, Instant Power Slow Drain is safe to use in blocked toilets, waste disposals and septic tanks, as well as other drains around the home. So if your loo or even your washing machine isn’t emptying as fast as it should, this is the product to use, rather than anything containing caustic soda. It won’t work on solid blockages, but it’s environmentally friendly enough to be used daily, so you could put a couple of capfuls down the sink each night to keep things flowing and stink-free.
Key details – Size: 1l; Type: Enzymatic; Format: Liquid
6. Ecozone Enzymatic Drain Sticks: Best drain unblocker sticks to keep sinks flowing
Price when reviewed: £5.12 (12-pack) | Check price at Amazon
Shoving a long, thin stick down the drain and wiggling it about may seem like the oldest unblocking trick in the book, but British company Ecozone has added the power of enzymes to produce a new innovation: enzymatic cleaning sticks. These Vegan Society and Allergy UK-approved sticks are designed to be as environmentally friendly as possible, using powerful natural bacteria to break down clogs and keep your pipes and drains moving.
Simply insert a single stick into the plughole or drain, then leave it for a month while it gets on with the job of keeping blockages from forming. With 12 sticks in each pack, that’s enough to last you a year. They’re fantastically useful for keeping water flowing through bath and sink plugs, but to unblock really serious drain clogs you’ll need something stronger.
Key details – Size: 12-pack; Type: Enzymatic; Format: Sticks
How to choose the best drain unblocker for your home
Does it really matter which drain unblocker I buy?
Most chemical drain unblockers are based on caustic soda (sodium hydroxide), which eats through blockages without damaging pipes. But caustic soda is not the right choice for all blockages and could be dangerous if used on a toilet, waste disposal or any other unit that’s likely to overflow when blocked. So to clear clogs effectively and safely, choose the right one for the job.
Solid blockages in your kitchen and bathroom pipes, including shower wastes and kitchen sinks, are best cleared using chemical-based drain unblockers. Their caustic ingredients produce gaseous heat that dissolves blockages including congealed fat, soap-scummy hair and even limescale.
For best results, try loosening the blockage with a plunger and hot water first. Never use a plunger after pouring a chemical unblocker.
Pipes and drains that aren’t fully blocked can be tackled using enzyme-based drain unblockers, which are gentler than chemical unblockers. They contain bacteria cultures and concentrated enzymes that effectively digest organic substances such as food and mould, and will continue working long-term to prevent further build-up.
The main disadvantage of enzymatic unblockers is that they won’t eat through solid blockages. They need to be able to flow through the pipe to get the job done. So if you want to avoid chemical unblockers, loosen blockages using a plunger and boiling water before you go in with an enzyme-based unblocker.
Toilets and waste disposals should only be tackled using plungers and enzyme-based drain unblockers, never with caustic soda products.
Will a drain unblocker damage my pipes and sink?
Stainless steel sinks and plugholes can be corroded by chemical unblockers, so take care when pouring.
All our recommended products are in liquid or gel format. Not only are they easier and safer to control than powder or granular products, but they also work more effectively because they cling to pipes to ensure everything is cleared. Powder unblockers can form clumps, causing corrosion and making blockages worse. They can also be breathed in, so if you must use them, wear a mask and goggles.
PVC pipes are now standard for drainage in the home, including shower and kitchen sink waste traps. All the chemical and enzymatic unblockers we recommend say they’re safe to use on all pipes, including PVC. However, some damage is hard to avoid if you use the product a lot over an extended time. Enzyme-based unblockers cause less damage in the long term but remember they only work if the pipe isn’t fully clogged in the first place.
