Water bosses are warning Lancashire residents, particularly the elderly, to watch out for criminals posing as water board officials.
United Utilities is warning people to be on the lookout against bogus callers and opportunist burglars.
The company said offenders call saying they are from the water board. They ask you to turn off the water and then steal from your property while you are distracted.
The warning comes as the nights become brighter and people knock on doors into the evening.
United Utilities added: “We very rarely call without an appointment. Always ask for an identity card before letting anyone into your home.”