Water
From Captain of Industry Wiki
Water
Water, notably fresh water, is a natural resource obtained through pumping groundwater tables with a Groundwater Pump or collected with a Rainwater Harvester. It is most useful in the early game for making Concrete Slabs in the Concrete Mixer and processing Impure Copper in a Copper Electrolysis. Mid-game it is widely used for petrochemical chains and in steam power production.
Note that groundwater reserves are finite and replenished only by rainfall. It can be dumped into the ocean with a Liquid Dump, though given the abundant number of recipes requiring it and the ability of groundwater to run dry, this is not recommended in most cases.
Each World Map has a Groundwater Well from where an unlimited amount of water can be imported.
