A 92-year-old woman is among four victims of bogus workmen in one week.
Police are investigating three incidents over the weekend in Mirfield, Dalton and Slaithwaite and are linking them to a fourth incident in Fartown last Tuesday.
In each incident, two bogus water officials have targeted elderly residents.
Detective Constable Julian Burgin said: “We had three incidents of bogus officials this weekend.
“We don’t want anyone to panic, but we are doing all we can to stop any more elderly people being targeted.”
The incidents happened at Greenside in Mirfield at 2.15pm and at 4pm at Wakefield Road in Dalton, both on Saturday.
While the 92-year-old woman was targeted at her home on Varley Street, Slaithwaite at around 10pm on Friday.
In each incident, men claimed they worked for the water board and were checking stop taps in people’s homes or working on a burst sewage pipe.
The Slaithwaite woman was told to fill buckets of water because her water supply would be switched off the next day.
But in every incident, a second man entered the house unbeknown to the resident and stole cash while the homeowner was distracted.
Detective Constable Steven Dobson of Kirklees Police said: “The Slaithwaite victim was a 92-year-old lady and of course she was very shaken.”
The fourth incident happened at 2.30pm last Tuesday, March 11, at a property on Hillhouse Lane when a 68-year-old woman was targeted.
The woman allowed one man to enter and run the taps in her kitchen, without realising that another man had sneaked into her house and stole cash from her bag.
The men said they were working on a burst sewage pipe in Fartown.
Police say the suspects in every incident were white men.
One is described as being of slim build aged in his early 20s, 5ft 9ins tall with short dark hair and was wearing a navy fleece with a logo.
The other man is also aged in his 20s and wore a hat. Both may have had an Irish accent.
Police are now advising all homeowners to ask for identification from anyone saying they are work officials and need access to your home.
Their advice is to refuse entry until identification is proven, and if in doubt call the company concerned to clarify if any work is taking place.
Alternatively call police if they are acting suspiciously.
Anyone with information is asked to call police on 0845 6060606 or Crimestoppers on 0800 555 111.