Would you drink sewage? What millions will be asked as suppliers desperately try to beat water shortages Thames Water supplies 3.5million homes in London and Thames Valley It will face a deficit of 125million litres a day in 10 years if no action is taken Customers will be asked for their views on drinking recycled toilet water Millions of families are being asked if they would drink water from recycled sewage to avoid shortages Millions of families are being asked if they would drink water from recycled sewage to avoid shortages. Thames Water, which supplies more than 3.5million homes in London and the Thames Valley, will face a deficit of 125million litres a day by the end of the decade if no action is taken. That is roughly equivalent to the amount needed for a million baths. As well as reducing leakage and wastage, and introducing more water meters, the company is now asking customers for their views on drinking recycled toilet water. Reusing waste water is common in drier climates such as Australia, Spain and the US, but a relatively untested technology in Britain. It involves putting treated effluent from a sewage works back into a river upstream of a water treatment plant. The diluted waste is then treated to drinking quality standards before being supplied to customers. With London's population continuing to grow, its ageing utilities are struggling to keep up with demand. By 2040, Thames Water will have a 16 per cent deficit if it does not boost its output - leaving 2.2million people short of water. Recycling sewage into drinking water is being considered to meet shortfalls from 2025, with the most likely site in east London, under the firm's draft resources plan for 2015 to 2040. Currently, Thames Water is investigating recycling used household water - including effluent from dishwashers, washing machines, baths and toilets - at a plant in Enfield, north London. None of the water is being put back into supply. The company said the claim that water drunk in the capital has already gone through the human body seven times is a myth. Recycling sewage into drinking water is being considered to meet shortfalls from 2025, with the most likely site in east London, under Thames Water's draft resources plan for 2015 to 2040 By 2040, Thames Water will have a 16 per cent deficit if it does not boost its output - leaving 2.2million people short of water But it did admit that a small amount of today's drinking water could come from waste, with treated sewage from locations such as Reading and Oxford discharged into the Thames before being purified at downriver plants and pumped to residents in London. The fact that consumers have already been drinking reused water may help convince them not to reject the method. Thames Water said: "After 2025 we are likely to require a major new source of water. On the basis of what we know now, this would be either a large new reservoir or a major water transfer scheme from elsewhere in the country or significant reuse of waste water. The purpose of the consultation is to explain the pros and cons of all these options to our customers and seek their views. Most utilities get their supplies from two major sources, rivers or groundwater - the latter tends to be cleaner. After being passed through grilles to remove large items of debris, the water is pumped into plants where chemicals are added to help remove finer particles such as mud and silt. It is then passed through a fine filter, often a bed of sand which contains micro- organisms that provide additional cleaning by breaking down any organic compounds. The water is then aerated to remove pesticides and any remaining organic compounds, helping to achieve a more neutral taste. In the final stage, chlorine is added as a disinfectant before the water is supplied to the consumer.