South West Water has discovered its largest ever fatberg in a Sidmouth sewer under The Esplanade.
The congealed mass of fat, oil, grease and wet wipes is longer than six double decker buses and is expected to take around two months to remove.
Sewer workers are due to start the mammoth task on Monday 4 February but could be delayed if the area experiences heavy rain.
Andrew Roantree, director of wastewater at South West Water, said: “It shows how this key environmental issue is not just facing the UK’s cities, but right here in our coastal towns.
“It is the largest discovered in our service history and will take our sewer team around eight weeks to dissect this monster in exceptionally challenging work conditions.
“Thankfully it has been identified in good time with no risk to bathing waters.”
The company has warned customers about the “significant consequences” of cooking by-products going down the plughole and items which should not be flushed entering the sewers.
Roantree added: “If you keep just one new year’s resolution this year, let it be to not pour fats, oil or grease down the drain, or flush wet-wipes down the loo. The consequences can be significant – including sewer flooding in your own home.
“Put your pipes on a diet and don’t feed the fatberg.”
Sewer workers will require full breathing apparatus to carry out the removal, which will involve a combination of manual labour and special sewer jetting equipment.
South West Water said it “proactively identified” the blockage during routine checks of its 17,000km sewer network.
The company tackles a new sewer blockage at a rate of one an hour which it says adds £4.5 million to bills every year.
Thames Water installed a “special edition” manhole cover in September last year to mark the first anniversary of the discovery of the 130-tonne infamous Whitechapel fatberg.
The 250-metre long blockage hit headlines around the world after it was discovered in an east London sewer in September 2017. It took sewer teams 13-weeks to remove it.
Thames Water said it has since tripled its above ground “fatberg-fighting team to work with restaurants and takeaways to trap fat in kitchens.
Research by the water company suggests two-thirds of Londoners are now aware of fatbergs.
Every hour Thames Water clears five blockages from its sewer network, which can cause pollution to the environment or customer’s homes. The blockages are caused mainly by flushed wipes at a cost of around £12 million every year.