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Experts at Portsmouth University say as a country we'll pour 15 million cups of roast turkey fat down the kitchen sink on Christmas Day, enough to nearly fill an Olympic swimming pool.
Their research has shown how fat transforms into a hard soapy material when poured into the sewers, creating major problems for water companies.
The cost of cleaning sewer pipes and removing fat, oil and grease is estimated to add £50 million a year to our household bills.
Dr John Williams, from the University of Portsmouth, said: ''Millions will have stretched their finances to the maximum to pay for Christmas without realising they might be storing up hidden costs for later by pouring cooking fat down the kitchen sink.
Householders who pour fat down the plughole might as well be pouring money down the drain.
Many people do not understand how a modern city runs, which is why sewers are abused.
Sewer systems are designed to use water to transport waste, so adding fat, oil and grease to that leads to sewer clogging and system failure.
The costs of removing fat, oil and grease from the sewers are inevitably passed on to consumers.
Nobody budgets for this, but we all pay the price.''
He added that sewer blockages also pose serious health risks through the danger of toilets backing up and sewer overflows.
Dr Williams explained that once poured down sinks, the oil from the fat transformed into a hard, chalky substance, a bit like soap, which was very hard to remove.
He added that the culprits, whether they be takeaway restaurants or specific homes, were difficult to pinpoint.
Dr Williams said his research into how this substance forms would help water companies remove it and reduce their costs.
He explained that the two main causes were the fatty acids transforming from unsaturated to saturated forms, which is helped along by sewer micro-organisms.
The other was linked to the way fat, oil and grease deposits form in hard water areas, he said.
Increasing water hardness is associated with increased calcium levels in fats, oil and grease, making the residue harder to remove.
Southern Water has asked customers not to pour fat down the drain.
Southern Water's head of wastewater, Simon Parker, said: ''We always notice an increase in fat in the sewers around this time of year as so many people are at home cooking Christmas dinners and more fat than normal ends up down the sink.''