To check water supply turn off water and remove hose/s while water pipe/s are off check water supply output by running pipes into a bucket turn water on if OK move to the rear of machine and find and clean out the water filters
If water supply is only a dribble,you may have low mains pressure or check and see if you have these self cutting taps fitted, these rust up the hole due to the small size of hole.
As for the filter this should be cleaned out REGULARLY
wirecutterman
March 2009