You might be interested in using the water pumps in Once Human if you don’t want to waste time manually moving water from your collectors to your purifiers. However, the pumps don’t work quite how you would expect.
A normal assumption would be that they have an input and an output but this isn’t the case. All you can do is attach pipes to the pump and view the flow of the water when you have pipe visibility enabled. Let’s go over how the water pumps in Once Human work and how you should set them up to have a fully automated water purification process.
How Once Human’s Water Pumps Work
The reason many players are confused by the water pumps in Once Human is that they work off of a gravity-based system. Instead of having an input and output to push water through when powered, the water pumps pull water from a pipe below them and push water up a pipe above them. This means that in order to have a working setup, you need to have your water collectors below the water pump and whatever you are moving the water into above the pump. Similar to the setup shown below.
You will also need to have power for the water pump, as it will only work when supplied with power. Without power, the water will follow the natural flow of gravity. So any water will work its way down the piping system, turning your water collector into your storage and leaving your storage empty.
Since the water system works by following gravity, you can get away without the use of a water pump if each piece is below the last. But you will need to keep in mind that not the pipe height is based on where the connection point is for the object and not how tall the object is. Something like the rainwater collector has a pipe connection at the bottom of the object. While the water purifier has a connection point for pipes at the top. This means that if you place it on the same level, you will need a pump to move the water out of the collector into the purifier despite the collector being much taller.
Hopefully, this has explained how not only the pump but also the water system in Once Human works. Now you can set up your automatic water purification system so you will always have clean water to drink and water your crops with.