Thames Water is spending £1 million every month to clear fatbergs from its sewer network – with four areas named as the worst offenders.

Thames Water has revealed this week that fatbergs are wreaking havoc in the sewers of Bromley, Mole Valley, Epping Forest and the Royal Borough of Windsor & Maidenhead - a total of 14,137 blockages have been cleared from the four areas in the last three years.

Formed when leftover cooking fat and wet wipes congeal into a solid mass in sewers, fatbergs – which cost the company £1 million a month to clear – block pipes and can cause sewage to back up into people’s homes and gardens.

In a bid to alleviate the problem, Thames Water has launched a widespread campaign this week urging its customers to ‘Bin it – don’t block it’ when it comes to anything other than toilet paper and human waste.

As part of the campaign around 300,000 homes and businesses will receive advice in the post along with details of how to order a free fat trap to help them dispose of used cooking fat in the bin rather than pouring it down the sink. Billboard and bus stop posters will also be appearing across the four hotspot areas during the six-week campaign.

Thames Water’s head of customer field services, Jerry White, said:

“Often people don’t realise the consequences of putting things other than human waste and toilet paper down their toilets and drains but it’s time for everyone to understand and take action. It’s not just fat that’s the problem but wipes are a massive issue too. Many will be labelled as “flushable” and they may disappear when you flush the toilet, but they don’t break down once they get into the sewer pipes. These wipes seem to be in most of our homes now so we all have a responsibility to do the right thing and put them in the bin.

“Blockages will often lead to sewage flooding homes, businesses and the environment and in Bromley, Mole Valley, Epping Forest and Windsor & Maidenhead this is a regular occurrence. It is damaging, hugely distressing and, in many cases, avoidable. We hope our campaign will educate people and encourage them to ‘Bin it – don’t block it’. We’ve got thousands of fat traps to give away so order yours now.”

Blockage figures published by the water company show:

• Borough of Bromley – 5,810 blockages cleared in last three years
• Mole Valley – 1,523 blockages cleared in last three years
• Epping Forest – 3,030 blockages cleared in last three years
• Royal Borough of Windsor & Maidenhead – 3,774 blockages cleared in last three years

Thames Water’s sewer operations specialist for Bromley, David Theobald, added:

“The sewers serve an important purpose – they are not an abyss for household rubbish. Cleaning pots and pans with washing up liquid does not break down fat, oil and grease for good. When it hits the cold sewers, it clings to wet wipes and hardens into gruesome fatbergs which cause blockages in the pipes. Wet wipes aren’t the only problem – we often find condoms, nappies, tights, tampons, cotton buds and syringes in fatbergs too.

“Every day my team spend hours removing these blockages which increase wear and tear on the pipes. The more fatbergs there are the more damage they cause, which inevitably results in us having to dig up roads to fix broken sewers – all of this causes disruption to our customers, and ultimately makes an impact on customer bills.”