Don’t feed the fatberg: Thames Water reveals the top habits that could be wrecking your pipes
- New research carried out by Thames Water has revealed that among those surveyed, the most poured substances in the kitchen sink this past month included milk (61%) and meat juices (31%).
- Meanwhile in the toilet, a quarter (25%) of those surveyed believed that disposable wipes were safe to flush down the toilet.
- Pouring fats, oils and grease (FOG) down the kitchen sink is one of the leading causes of blockage-related internal flooding.
- Every year, Thames Water clears up to 75,000 blockages which on average costs up to £40 million annually to unclog and remedy.
- This festive season, Thames Water is encouraging its customers to bin the grease from Christmas meals and avoid flushing Christmas dinner napkins down the toilet so we can all keep our pipes flowing freely and prevent costly blockages caused by fatbergs.
With winter and the festive season fast approaching, Thames Water is encouraging households to be mindful of what goes down the drain.
New research commissioned by Thames Water has revealed that households across London and the Thames Valley are unknowingly contributing to blocked pipes, polluted waterways and increased risk of internal flooding through everyday disposable habits.
The survey of over 2,500 adults found that milk (61%), meat juices (31%) and oils such as sunflower, olive, rapeseed, vegetable and canola (26%) are among the most commonly poured substances down the kitchen sinks.
While these acts may seem harmless at first, they can congeal and combine with other waste over time to form fatbergs – solid masses that block pipes, wreak havoc on drainage systems and, in the worst cases leading to homes being flooded with sewage and pollution in our rivers
Fats, Oils and Greases (FOG) account for 28% (20,000+) blockages in the Thames Water network annually and can cost up to £11m a year in clearance and repairs.
In the bathroom, confusion persists - mainly due to confusing labelling on toiletry products, with a quarter (25%) of respondents being under the impression that disposable wet wipes are safe to flush down the toilet.
In the past month one out of ten surveyed stated that they had flushed kitchen roll or sanitary products down their toilet.
These behaviours have a real consequence with nearly half (46%) of those surveyed citing that they have experienced a blocked sink and four out of ten (41%) stating that they have experienced a blocked toilet and three out of ten (35%) saying they have had a blocked drain.
The survey also found that a staggering majority of those surveyed are aware of the environmental risks, with eight out of ten (83%) responding that they were aware that pouring or throwing of inappropriate items down the sink or toilet can lead to pipes being blocked.
Despite this outlook, they also pointed out that more needs to be done to address and quash these habits among the general population. These included clearer packaging labels and using separate bins for food and liquid disposal to go next to the kitchen sink which are supplied by local authorities.
Tess Fayers, Director of Wastewater and Bioresources at Thames Water, said: “Our research shows that everyday habits like rinsing leftover food, oil and fatty liquids down the sink or flushing wipes can unintentionally lead to blocked pipes. These issues are especially common during the festive season, when cooking and hosting are in full swing.
“The last thing we want is for the festive season to be ruined by blocked drains. There are some simple changes we can all make to help protect our homes and keep sewers flowing.
“Always scrape fats and oils into the bin before washing up, avoid pouring drinks like hot chocolate or tea down the drain, and avoid flushing anything that isn’t pee, poo or toilet paper, even if the packaging says otherwise. These small steps can make a significant difference to our environment and help protect homes for everyone; not just for the festive season but for years to come.”
Recently, Thames Water, in collaboration with the Port of London Authority (PLA) and Thames21 removed 114 tonnes of congealed wet wipes from Wet Wipe Island, near Hammersmith Bridge.
The operation, which was an industry first, aims to improve river health in the Thames and raise awareness of how inappropriate disposal habits can lead to environmental damage.
Top tips on how to starve the fatbergs this festive season:
- Scrape food scraps from any dirty dishes, pans or utensils into the bin, or ideally a food waste caddy and not into the sink.
- Ensure your plughole has a basket strainer fitted to catch food scraps and prevent them from going down the drain.
- Avoid flushing coffee grains down the sink, even with plenty of soapy water. Many supermarkets have designated bins specifically for coffee grounds. If you are an avid gardener, or know someone who is, you could keep them for composting.
- Don’t pour liquid foods down the sink i.e. yoghurt, gravy, milk or soup.
- To dispose of surplus hot oil, let it cool, then scrape it into the bin or consider storing it in a container to take to the local recycling centre.
- Avoid pouring boiling water or bleach down the drain – this only moves the problem further down the pipes and does not resolve the issue.
- Only flush the three Ps down your loo – Pee, Poo and (toilet) Paper. Do not flush wet wipes, cotton buds or paper towels.
- Always clean your drain regularly – if it looks like it’s draining poorly, better to sort it sooner rather than later.
Further Information:
Find out how you can starve the fatberg on our ‘Bin it - don’t block It’ page
The research was conducted by Opinion Matters, among a sample of 2,501 adults (18+) living in London, Oxfordshire, Wiltshire, Berkshire, Surrey and Buckinghamshire. The data was collected between 29.10.2025 - 06.11.2025. Opinion Matters abides by and employs members of the Market Research Society and follows the MRS code of conduct and ESOMAR principles. Opinion Matters is also a member of the British Polling Council.