Fat, oil and grease

Fat, oil and grease often ends up being washed down the kitchen sink – but this can harden, blocking pipes and causing pollution.

Fats and oils collect inside the sewers. Over time, they harden to a concrete-like material and restrict the flow of wastewater in the pipes.

These blockages can cause wastewater to back-up through toilets and sinks into homes and businesses – or escape through manholes into streets and rivers.


How to prevent fat, oils and grease blocking sewers

Our sewers are only designed to take away the three Ps – pee, poo and paper.

In the kitchen, follow our top tips to avoid fat, oil and grease building up in the sewer.

  • Use containers – butter tubs, yoghurt pots or jam jars can all be used to collect cooled fat and oil – then just put them in the bin
  • Clear your plates – scrape any leftover food or grease and fat residue from plates, pans or cooking utensils into the bin
  • use a bin – put a bin in your bathroom for anything that isn’t pee, poo or paper
  • bag it and bin it – use scented nappy sacks or dog poo bags for any rubbish that may cause a smell
  • compost your food waste – collect uncooked fruit and vegetable peelings for use as compost in your garden
  • strain it – use a sink strainer or drain protector to stop hair blocking your drain.


What's it like in the sewers?

Every day our team of operatives work to keep our sewers flowing smoothly. Follow a day in the life of one of our sewer operatives in the film below.


Fat facts
  • More than 3,000 homes are flooded in the UK each year because of fat, oil and grease blockages
  • £90 million is spent every year on clearing fat, oil and grease blockages across the country – money that could be passed to you in savings
  • As well as causing blockages leading to flooding, build-ups of fat, oil and grease can also put wastewater pumping stations out of action.
Environmental impact

These blockages – from fat, oil and grease or from unsuitable items being flushed away – can have a harmful effect on our environment.

This could be sewer flooding in your neighbourhood or pollution in local streams, like in the image above.

Washing machines, toilets and other items may be plumbed incorrectly in some homes, meaning dirty water and other waste is sent directly to streams and rivers instead of to treatment works to be cleaned. Find out more below.

Misconnected pipes - bad plumbing and pollution

What to do if your drains are blocked


Fat, oil and grease in our sewers

Our contractors regularly send cameras into our sewers to find the cause of fat blockages. The film below shows this in action in a sewer in Kent.