The Whanganui District Council is reassuring residents the city's drinking water is safe and to ignore a water filter scam.
Council chief executive Kym Fell said scammers are phoning people saying they ware from the council and water in the area was contaminated.
They then arrange an appointment to visit residents and sell them a filter.
Mr Fell said the callers were not from the council and the district's water supply was perfectly safe to drink.
He said the scammers' behaviour was despicable, especially because they were targeting the elderly and people who live alone.
Mr Fell said the council had reported the scam to the police.