We have two Harris Farms One Gallon waterers, but only one stays filled in the coop. The other one stays in the house.
We check on the chickens each morning and evening, so each time we go out there, we bring a freshly filled waterer. Take the old dirty one back to the house, rinse it out, set it on a shelf by the sink, and it's ready to go for the next time. Fill it up and take it out there when we go next... lather, rinse, repeat.
Works out great, because our young daughter is the main chicken caretaker, and the one gallon waterers aren't too heavy for her. Plus, the chickens get fresh water twice a day.
These waterers are not the kind with the screw off top (she couldn't get them tight enough to create a good seal, and they leaked). The BOTTOM of these waterers comes off and goes back on with a quarter turn-- much easier!