Top of the blocks: Sewer blockage hotspots revealed

Hounslow had more sewer blockages than any other local authority in London and the Thames Valley over the last year, new Thames Water figures have shown.

The West London borough had more than 3,150 blockages between November 2019 and October this year, just 12 more than the next highest, Enfield. This equates to more than three blockages for every 100 homes in the area. In the Thames Valley, the authority with the highest number of blockages was Swindon (1,332).

In Hounslow, more than 1,200 blockages were caused by items which don’t break down in sewer pipes, such as wet wipes, nappies and sanitary products, while almost 1,600 more were caused by fats, oils and grease poured down the sink.

These can combine to create fatbergs: huge, solid masses which are difficult to clear and can cause raw sewage to build up and flood homes, businesses and the environment.

Matt Rimmer, Thames Water’s head of waste networks, said: “Sewer blockages caused by unflushable items being put down toilets and sinks pose a massive problem, risking raw sewage backing up into homes or businesses and costing millions of pounds to clear.

“They can cause massive and disgusting fatbergs that take a great deal of effort and teamwork to clear and get the sewer working well again. Many items like wet wipes have plastic in them and won’t break down in the sewers, even if they say they’re flushable.

“We’d urge everyone to help by only flushing the 3Ps – pee, poo and paper – as well as disposing of fat and oils in the bin, not the sink.”

Making up the rest of the top 10 was Bexley (2,990), Havering (2,844), Hillingdon (2,833), Brent (2,712), Redbridge (2,689), Ealing (2,606), Barking and Dagenham (2,409) and Newham (2,384).

At the other end of the scale, Gravesham in Kent recorded just one blockage, while Horsham (six), Tonbridge and Malling (seven) and the City of London (eight) all kept blockages down to single figures.

On average, Thames Water spends £18 million every year clearing 75,000 blockages from its sewers, unclogging five house blockages and removing 30 tonnes of material from just one of its sewage treatment works every day.

Instead of pouring fats and oils down the sink, customers are advised to collect them in a container, such as a yogurt pot or jam jar, and leave them to cool down before scraping them in the bin. Wet wipes, sanitary items, nappies and other toiletries should also be binned rather than flushed down the toilet.

During the first national lockdown this year, up to one in five customers admitted using alternatives to toilet roll after struggling to get hold of it in shops. This led to blockages increasing by almost 20%.

Earlier this month, Thames Water launched its annual ‘Bin it - don’t block it’ campaign, encouraging customers to be vigilant about what they put down their sinks and toilets.

As part of the campaign, the company has partnered with recipe box delivery businesses Red Rickshaw and Feast Box, who will include leaflets in their deliveries asking customers to safely dispose of fats and oils when they have finished cooking.

The company’s network protection team also visits food establishments across the region, ensuring they are not putting fat, grease and oil down their sinks and that fat traps are installed and working properly. 

Businesses that allow fat, grease and oil to get into sewers can face prosecution, fines of hundreds of thousands of pounds and may even be forced to close.

For more information visit the 'Bin it' campaign page.