Northumbria Police lodged an appeal for information last week, following the incident in Bedlington. It was reported that a man knocked on the door of an elderly person, claiming to work for Northumbrian Water.
While he distracted the person, it is believed a second person entered the home and stole £5,000 in cash.
In January, Cleveland Police say two elderly people in Redcar had money stolen by people claiming to work for Northumbrian Water and that they needed access to their homes to make urgent checks.
Northumbrian Water employees always carry identity cards and do not mind handing the card to customers and waiting outside while the resident calls the company to check the person is who they say they are.
This is just one tip the company gives to help customers keep their homes safe from unscrupulous tricksters who want to gain access to a property for the purposes of theft.
Many such criminals claim to be from their local water company and use terms such as "the water board", which is an outdated phrase the company doesn't use.
Northumbrian Water also operates a service where customers can set up a password, so that they can use this to check the validity of a caller at their home when they claim to work for the company.
Dawn Creighton, Northumbrian Water's Head of Customer Service, said: "These incidents highlight the threat such con artists pose to people across the North East and we would advise customers to be very careful about who they let into their home.
"One way of checking that a caller is bona fide is by setting up a password with us, which is something that can be done online or over the phone.
"Also be particularly cautious of any caller who claims to be from ‘the water board'. This is an old term and we do not use it.
"The other measure people can take is to keep the person outside, get them to pass their identity card through the letter box, or through the gap in the door if the chain is on, and call us on the number -
0345 7171100 - on the back to make sure they are genuine. Our people don't mind, because they know that customers' security and peace of mind is a priority.
"People can also find information on our password scheme at www.nwl.co.uk/priorityservices
"If in doubt, keep them out until you know they are who they say they are."