Water
Water, notably fresh water, is a natural resource obtained through pumping groundwater tables with a Groundwater Pump or collected with a Rainwater Harvester in the early-game. It is most useful in the early game for making Concrete Slabs in the Concrete Mixer and processing Impure Copper in a Copper Electrolysis. From mid-game, water is also obtained by Groundwater Well in World Map and Thermal Desalinator, and it is widely used for petrochemical chains and in steam power production.
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.
Groundwater and rainfall
Groundwater reserves are finite and replenished only by rainfall. The rate of replenishment is seemingly dependent on the size of the reservoir, i.e. reservoir containing 15 000 units of water replenishes 14 units of water per day during rain, and 12 000 unit reservoir replenishes 11 units of water per day. Heavy rain has twice the rate of replenishment. Since the Rainwater Harvester generates only 0.5 units of water per day of rain, we can assume that a 15k reservoir generates 28*40=1120 units of water per year. Assuming that 15k reservoir is worth 28 rain collectors, and each captures 40 units of water each year. Rain seems to replenish 2.5 units of water per day in a Farm.
