Some cats do not like to have their water next to their food. Try moving the food or water bowl so they are not next to each other. Maybe not even within smelling distance. Some cats want very fresh water with no dust or cat hairs in it, so you might need to change the water bowl more often. And wash it daily. It does seem, with my cats anyway, that mostly they don't want to drink next to their food. Their favorite place to drink from is a bowl set in the bathtub/shower combo which we don't wind up changing out much during the day, so water sitting a few hours is fine with them- as long as it is in the bathtub. We finally just put a bowl in the tub as they kept licking the sides and I didn't want them licking up soap scum.
Is the water bowl plastic? Plastic "flavor" gets into water, which is why I hate drinking from plastic cups. Try using a stainless steel or ceramic bowl in addition to not having it next to the food.
My cats like to drink out of a glass of water sometimes too. I sometimes keep a short glass of water on the sink counter for them. Two of them sometimes slurp from the faucet. Sometimes I turn it on for them to get a drink if they are doing that. Anything to get them drinking more, since cats do not normally drink much, being evolved to extrude moisture from prey (as in blood), something most pet cats don't get to do. Cats eating mostly dry food really need to drink more than they might naturally be inclined to.