At Waterwise, we spend a lot of time thinking about how the choices we make in our homes affect the wider system that keeps water flowing safely to and from our taps. Christmas is a time of warmth, cooking and celebration, but it’s also the time of year when fats, oils and grease (FOG) rise sharply in our sewers.
Before joining Waterwise, I spent several years leading the Keep it Clear Programme at Anglian Water, working directly with communities and seeing first-hand how small, well-intentioned habits can build up into serious issues. Much of the pressure on our sewer system is completely avoidable and Christmas is the perfect moment to focus on the changes that make a difference.
Why FOG matters – the scale of the problem
Across the UK, water companies deal with around 300,000 sewer blockages every year, at a cost of more than £100 million. Around 70% of these blockages are linked to FOG and unflushable items. In some regions, including areas I previously worked in, up to 80% of sewer flooding incidents are linked to fats, oils, grease and wipes.
FOG from roasting tins, gravy, butter, oils and meat juices may leave the kitchen hot and liquid, but once in the pipes it cools, sticks, and hardens. It builds up layer by layer on the inside of sewer walls, creating the perfect surface for other materials to attach to.
And that’s where the link to wipes becomes unavoidable.
FOG + Wipes + sanitary products = The Ingredients of a Fatberg
Even when fats and oils have started forming a sticky coating inside a sewer, it is often the wipes – baby wipes, make-up wipes, cleaning wipes, and sanitary products – that bind to the FOG and help create the enormous fatbergs we hear about in the news.
Wipes don’t break down in the sewer system. Instead, they snag, knot together and cling to grease deposits. Together, wipes, sanitary prducts and FOG create dense, cement-like blockages that:
- reduce sewer capacity
- increase the risk of sewer flooding in homes and streets
- cause avoidable pollution to rivers and the environment
- require water company network teams to physically remove them, often under very challenging conditions
This is why tackling FOG and wipes/sanitary products must go hand in hand.
Reducing FOG at home – and saving water too
There is also an important water efficiency point: when we rinse greasy trays, pans and plates under the tap, we use large amounts of clean drinking water simply to push grease into the sewers, where the greasy water it eventually becomes part of the problem.
Small changes really do help:
- Wipe first, then wash. A quick wipe with kitchen roll removes grease before washing, saving water and protecting the sewer network.
- Let fats cool and scrape them into the bin or food waste.
- Use a “fat jar” for leftover cooking oils.
These are practical steps that prevent blockages and reduce water waste at the same time.
Wipes: plastic-free doesn’t mean flushable
The new legislation requiring wipes to be manufactured without plastic is an important step for our waterways. But even without plastic, most wipes are not designed to break down when flushed or move through our sewers safely. Across the UK, millions of wipes are still flushed every year. Combined with FOG, they become the structural core of fatbergs.
So instead of framing this as a “rule”, it’s more of a shared understanding that protects all of us:
Only flush the 3Ps: pee, poo and (toilet) paper.
Everything else – including wipes and sanitary products – belongs in the bin.
A reflection for the festive period
While many of us will be spending time with family and friends, many wastewater network teams across the UK will be working throughout the festive period. They will be out on Christmas Eve, Christmas Day and New Year’s Day, often in difficult weather, stepping away from their own families to deal with avoidable blockages and protect our homes and the environment.
Their work is essential, and often unseen. One of the most meaningful things we can do to support them is simply to prevent blockages at home:
- Keep FOG out of sinks.
- Wipe before rinsing.
- Bin all wipes and sanitary products.
Individually, these actions are small. But collectively, they protect our rivers, our homes and the people who work tirelessly behind the scenes to keep everything flowing.
From all of us at Waterwise, thank you for doing your part to keep water flowing safely this Christmas.
– By Rachel Dyson, Project Manager
