We use poultry drinkers for chickens, plus one in the duck house when they're shut in for the night. In the day time, chickens and ducks all mix in together, and we've taken to simply providing the ducks with a full bucket of clean water every morning so they can dip their heads in, which they love. By the end of the day there's a layer of mud on the bottom of the bucket, so it's just a case of rinse it out and start again the next day.
They do have a pond, which we clean out regularly, but it always looks dirty, so we tried the clean water in a bucket thing, which seems to work OK for us.