Stories of gigantic fatbergs which are the size of a bus and smell worse than anyone could imagine appear in the news every now and then, but they may be a more common problem than you think and there is a lot you can do to prevent them.
Fatbergs are formed when oil, grease and fat poured down sinks solidify and often get combined with products like wet wipes and cotton buds to create a heavy solid which blocks a sewer.
Several giant fatbergs have been discovered in UK sewage systems this year, including one described as being the "size of a small bungalow" in London in February.
Sewage expert Steve Grebby told ITV News that dealing with fatbergs costs water companies around £100 million a year which is ultimately passed onto people's bills.
He also said pouring the wrong products down your sink or flushing the wrong things down the toilet can also bock the plumbing in your home with average repairs costing around £270.
Mr Grebby said the most problematic fatbergs are not the ones that often make the news about their size and smell but the smaller ones that block up small sewers.
"Most sewers are about six inches in diameter and it doesn't take a lot to block those up and when they do block up that sewage has to come out somewhere and usually that's from a manhole on the road or a property," Mr Grebby said.
What can be done to stop fatbergs forming?
"The basic advice is to make sure you're letting your cooking fat cool and then scrape it into the bin," Mr Grebby advised.
He said most people aren't aware they're doing it, when they go to clear a frying pan and pour the oil they had used down the sink.
Any amount of oil or fat used for cooking, whether in a roasting tray or frying pan, should not be poured down the sink.
Mr Grebby said some people believed mixing waste cooking fats with washing up liquid would help break it down but he said this was not the case.
When using large amounts of oil to cook with, for example when deep-fat frying, many councils advise the waste oil is poured into a container like a plastic bottle and put in the black bin.
The other big contributor to fatbergs and blockages in sewers is wet wipes.
Unlike toilet roll wet wipes are not designed to break down when flushed away.
Recently different companies and public services have come together to create a 'fine to flush' test which some wet wipes have passed and will break down after being flushed down the toilet.
Wet wipes that have passed the test should show a certificate on their packaging to let you know these are OK to be flushed down the toilet.
Other common products which get flushed down the toilet which aren't meant to are cotton buds and sanitary products.