Police are looking for witnesses following an incident in Weldon.
A man knocked at the door of a property in Oundle Road some time between 2pm and 3.50pm on Tuesday, January 3, saying he was from the water board and responding to an emergency.
He asked the woman at the property to run her kitchen tap and empty the cupboard underneath, during which time he went upstairs before leaving.
No items appear to have been taken.
The offender is described as a man in his 30s with dark brown or black hair and wearing a navy blue jacket.
Anyone with information should contact Northamptonshire Police on 101 or Crimestoppers anonymously on 0800 555 111.