Quick answer · updated 5 September 2026

How much does it cost to run a watermaker?

In energy: between 669 and 3,593 kWh over five years of daily use, depending on the system. In dollars: we do not publish a figure, because what a kilowatt-hour costs you depends on whether it comes from panels you already own or diesel through a genset.

Five years, leanest669 kWhSchenker Zen 30
Five years, thirstiest3,593 kWhRainman Modular AC 70L
The difference2,924 kWhfor identical water

Energy is the part that can be computed from published specs. The other three parts of a running cost — prefilters, membranes and chemicals; an annual service; and the occasional pump rebuild — are not published consistently by anyone, so we name them rather than estimate them. All three scale with hours run, which means an efficient system tends to be cheaper on those too.

Purchase price sits separately again, from $4,402 to $15,089 indicative across the table, before freight and installation.

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Where these numbers come from. Every figure on this page is computed at build time from the comparison table — rated output and rated draw as the manufacturer publishes them, with watt-hours per litre derived as one divided by the other. Nothing is typed in by hand, so nothing here can drift from the table. Where a figure is an assumption rather than a specification it is labelled as one. Methodology · the table.