If you have given your cat dry food, and she normally eats wet food, this could be a reason why is she drinking a lot of water and meowing. Dry food doesn’t provide your cat with water, causing her to seek more water than she normally does.
Your cat is more likely to drink a lot of water during hot summer days. If she’s also meowing - this is her way of communicating with you and showing you she’s in some distress. High temperatures can be difficult for felines, too.