A Water bottle will automatically satiate thirst, as the player lives in Project Zomboid.
A bottle of water will gradually lose its content, and will have to be refilled. To refill an empty bottle, it needs to be in the main inventory, followed by right-clicking on any water source (Sinks, Wells, Rain Collectors) and clicking "Fill empty bottle".
As of Build 31, water from rivers or Rain Collector barrels will be tainted, causing the player to become Sick. After a random amount of days at the start of a new game, the water works will be gone, and the character will have to survive on scavenged water or what is left in cisterns and house systems. Water Bottles are found in trash cans and refrigerators.
See the Water page for comparisons for water storage.