In Rust, drinking salt water costs you 20 hydration points, deals 2 health damage, and poisons you, so purifying water before drinking is essential for survival. You have two main options: a campfire-based water purifier available early game, and a powered water purifier for automated setups later on. There are also ways to collect clean water without purifying it at all.
Why Salt Water Will Kill You
Salt water is the most abundant water source on most Rust maps, but drinking it raw is worse than drinking nothing. Each sip drains 20 thirst points instead of restoring them, removes 15 hunger points, deals 2 health damage, and applies a poison debuff. If you’re desperate and near the ocean, resist the urge. You need to purify it first or find a freshwater source.
Rivers and freshwater lakes, by contrast, provide clean water you can drink directly or collect in containers with no purification needed. If you’re building near a river, you can skip purification entirely for basic hydration. But most coastal or desert bases will need a purifier.
The Campfire Water Purifier
The simplest purification method is the water purifier attachment for your campfire. It costs 1 empty propane tank, 15 metal fragments, and 10 cloth to craft, and takes 30 seconds to build. Once crafted, place it on a lit campfire.
To use it, fill a container (like a bota bag or water jug) with salt water from the ocean, then pour the salt water into the purifier while it sits on a burning campfire. The fire boils the water and converts it into fresh, drinkable water that collects in the purifier’s built-in reservoir, which holds up to 2,000 mL. You’ll need wood or other fuel to keep the campfire running during the process.
This method is reliable in the early game when you don’t have electricity. The downside is that it requires you to manually collect salt water, keep the fire fueled, and come back to retrieve the fresh water. It doesn’t scale well once your base grows or you start running farms.
The Powered Water Purifier
Once you have access to electricity, the powered water purifier is a significant upgrade. It requires 5 power (rW) to run and processes salt water at a much faster rate: roughly 720 mL of fresh water per minute. In practical terms, it converts 5,000 mL of salt water into 2,500 mL of fresh water in about 1 minute and 15 seconds.
The conversion ratio is 2:1. You put in twice as much salt water as you get out in fresh water. That sounds wasteful, but salt water is essentially unlimited if you place a water pump near the ocean, so the ratio rarely matters.
To set one up, you need a water pump drawing from a salt water source, a pipe running into the purifier’s “Water In” port, and a power source connected to the “Power In” port. The clean water output can then flow directly into a water barrel or into your base’s plumbing system.
Collecting Clean Water Without Purifying
Water catchers let you skip the purification step entirely because they collect rainwater, which is already clean. The small water catcher collects around 3 mL per minute in dry conditions, which works out to roughly 180 mL per hour. During rain, fog, or snow, collection rates increase significantly, potentially reaching up to 23 mL per minute.
The large water catcher collects about 8 mL per minute under normal conditions and has a 50,000 mL reservoir, making it far more practical for sustained use. If you’re running sprinklers for a farm or need water for multiple players, you’ll want several large catchers. In drier biomes with little rainfall, catchers alone may not produce enough, and you’ll need to supplement with a purifier.
Piping and Storage Tips
Water barrels hold up to 20,000 mL and serve as the main storage hub for any water system. You can connect purifier output directly to a barrel, then run pipes from the barrel to wherever you need water, whether that’s sprinklers, planters, or additional barrels.
Water pumps only push water in one direction and struggle with elevation. If your output pipe runs uphill from the pump, the water won’t flow. Place pumps as high as possible so gravity carries water downhill through your pipes. If you need water to travel upward at any point after the initial pump, you’ll need a second pump at that junction to push it higher.
For more complex setups, fluid splitters let you divide one water line into multiple outputs (useful for feeding several planter boxes from a single source), and fluid combiners merge multiple inputs into one line (handy for pooling water from several catchers into one barrel). A fluid switch and pump can act as a powered valve, letting you toggle water flow on and off or redirect it based on your needs.
Choosing the Right Setup for Your Base
If you’re a solo player with a small base near the coast, a campfire purifier and one or two small water catchers will keep you hydrated without any electricity. Fill a jug at the ocean, boil it on your campfire, and top off your thirst between runs.
For a mid-game base with basic power, upgrading to a powered purifier connected to an ocean water pump automates the entire process. Pair it with a water barrel and you’ll have a steady reserve without ever manually collecting salt water again. The 5 power draw is minimal, easily handled by a small solar panel or wind turbine.
Large bases running hemp or food farms need serious water throughput. Multiple large water catchers combined with a powered purifier feeding into several barrels will keep your sprinklers running consistently. Use fluid splitters to distribute evenly across your grow rooms, and place pumps strategically to avoid elevation issues in multi-story builds.