What Causes Blocked Drains, and How the Professionals Clear Them

Blocked drains are a huge problem in the UK, with more than 300,000 obstructions a year tackled by professional drain and water companies. The cost of clearing these blockages is estimated at more than £100 million annually, not counting the impact on local waterways, property damage, and incidents of raw sewage spillage.

Homeowners often attempt to clear a blockage themselves before calling a professional, in an effort to save money, but the answer is frequently beyond a DIY solution. But how much does professional drain clearance cost? Prices are mostly determined by the method of clearing the blockage and its location, but most homeowners pay around £100 for these services.

 

What blocks drains most often

The most recurring culprit of blocked drains is FOG — fat, oil, and grease.

When these substances are poured down kitchen sink plugholes, they very quickly cool, causing them to congeal and harden. Their cohesive nature means that they collect other debris within the drains, which eventually causes a blockage.

The second-biggest cause of blocked drains are so called ‘flushable’ wipes. Despite being labeled safe to flush, these wipes cause huge problems when put down the toilet. A 250-metre stretch of the Thames near Hammersmith Bridge became a ‘wet wipe island’ after years of accumulated deposits. The Port of London Authority removed around 180 tonnes of congealed wipes from the area in 2025.

 

How do professionals clear blocked drains?

Professional drain clearing companies use a variety of tools to identify and remove obstructions, including:

• CCTV cameras — Used to inspect the drain and establish where the obstruction is and what is causing it. Reasons for blockages include grease, fat, broken pipes, and tree roots.
• Mechanical augers — These flexible metal cables, commonly known as drain snakes, feature a hook or blade on the end to cut through, break up, or push out solid obstructions.
• A hydro jet — A device that uses highly pressurised water to blast away grease and fat build-up in drains and is even powerful enough to break up tree roots. The water is pushed through at up to 4,000 PSI.

 

When the drain is unblocked, the CCTV is often used again to check that all of the obstruction has been cleared away and that the inside of the pipe is clean.

 

What else obstructs drains?

There are other, everyday processes that can lead to a drain blockage, most of which can be prevented with regular maintenance.

• Clear out shower traps regularly, as hair strands build up, combine with soap scum, and create blockages
• Use paper towels to soak up oil, grease, and fat, then dispose of them in the bin rather than pouring the oil straight down the sink
• Scrape food remnants into a kitchen bin before washing up or putting plates in the dishwasher
• Switch from solid soap to liquid soap, which doesn’t produce soap scum, a major component of drain blockages
• Only flush toilet paper — nothing else is designed to break up in the same way. Other bathroom waste should go in the bin
• Flush a solution of white vinegar and hot water through your kitchen and bathroom drains once a month

 

There are plenty of steps homeowners can take to keep drains from getting blocked. Regular maintenance helps keep everything flowing, and common sense means you’re not putting things into the drains that shouldn’t be there.