More than three quarters of homeowners admit having water-wasting habits.
In a study by The Water Regulation Advisory Scheme (WRAS), one in five said they leave the tap running when brushing their teeth or washing their face.
As the nation basked in high temperatures this week, WRAS urged them to be more mindful when turning the tap to avoid the chances of water restrictions and hose pipe bans.
The water wasting habits British adults were most guilty of included not reusing water when preparing food, for 29%, taking deeper baths than necessary, among 26%, and filling the kettle up to the top rather than the amount needed, for 21.1%.
Other less common bad habits included having a shower after a bath and using a hose pipe to clean the car instead of a bucket.
Julie Spinks, managing director of WRAS, said: “Although everyday habits – such as leaving the tap on whilst brushing your teeth – might seem inconsequential, making a few small changes can make a big difference to the amount of water we use every day. We’re urging consumers to change at least one regular habit to help prevent needless water wastage.”