CHRISTMAS cooks are being warned not to wash oil and fat down the sink to help stop fatbergs in the sewers.

Pouring turkey drippings, oil, gravy and other festive leftovers down the plughole is a recipe for disaster that could make it a costly Christmas for unsuspecting households.

As millions of people across the north-west prepare to tuck into their Christmas dinner, water firm United Utilities is urging everyone to stop and think about what they pour down the sink and not run the risk of a blocked drain or seeing their home flooded with sewage.

Fatty substances put a huge strain on the sewer network and can create giant pipe-blocking ‘fatbergs’ which feast on our festive leftovers, enabling them to grow up to 250 metres long.

Blockages are one of the main reasons the number of properties across England and Wales flooded with sewage increased by almost a third in 2016/17.

Tony Griffiths, from United Utilities said: “Each year we tackle on average 28,000 blockages on the sewers which serve the North West, costing around £10 million.

"We are exploring different options to see how we can change attitudes and work with food outlets to make their kitchen sewer friendly, for example by installing fat traps to stop leftover food from entering the public sewer” he added.

Greasy leftovers can also clog up a property’s drains, landing the householder with a callout charge for someone to clear up the mess.

Steve Grebby, CCWater’s sewer expert, said: “We all love a surprise at Christmas but seeing your home flooded with raw sewage isn’t one of them.”

“There are lots of simple ways to safely dispose of leftover fat or grease, including letting these substances cool in a container before scraping them straight into the bin. It might cost you a little more time but it could save you a lot of money.”

The Cheshire-base water and sewerage firm which serves seven million domestic customers and 200,000 business customers

The water industry currently spends up to £100 million a year clearing blockages caused by inappropriate items being put down the plughole and sink, with customers footing the bill through their sewerage charges.

How to avoid a festive fatberg

1. Flush only the ‘three Ps’

Toilets and the sewage system are designed to take three things only – pee, poo and (toilet) paper. Don’t flush anything else – including baby wipes, kitchen roll, any sanitary products and cotton wool. Even nappies and tights have been found in the sewers, and needless to say, they don’t belong there.

2. Scrape plates

After Christmas dinner, scrape the plates and utensils well before washing them to get as much oil off as possible. Let the fat solidify first if that makes it easier to get rid of all of it.

3. Get a grease trap

You can get one installed, but a very simple alternative is to pour any oil and cooking fat into an empty milk container or margarine tub while it’s cooled but still liquid, and let it solidify in that rather than in your drains. Then chuck it away when it’s full. If you find there’s water collecting in the bottom, cut a hole in it and water your lawn before throwing it away.

4. Use the hair trap

You might be washing your hair more often than usual for all the seasonal parties. Make sure you’ve got a hair trap in your shower or bath plughole and throw the hair in the bin.

5. Don’t fall for the hot water myth

Some people might tell you that you can clear fat and oil from the drains by pouring hot water and washing up liquid down the sink. They’re wrong. Just don’t let fat go down there at all.