Yes water flossing can help to remove some plaque.
As long as the plaque buildup is not very severe then the water flossing can remove some of that plaque.
More severe plaque may need a dentist to remove the plaque but water flossing can remove some of the plaque.
I have had success in removing some plaque using a water flosser and it worked great but some more plaque that was more severe I had to have the dentist remove the plaque.
If you cannot get the plaque removed from your teeth at home then having a dentist do it is the best option for more severe plaque.
If you have a dental health insurance plan it should pay for the dental plaque removal.
The cost to remove plaque professionally from your teeth ranges from $1,000.00 to as much as $3,000.00