When you expose fresh or brown water to 1m of vacuum head it boils – losing all contaminants. So the then pump the steam to storage in a farm or printing works.
So each litre of pure water cost 0.008p. Mains water cost 0.097p . So 10 times more! And in actual fact vacuum is very cheap to produce – so this may be over estimating by a factor of 20.
So a farmer can install his vacuum pump on a stream, and get very nearly free water for his missals! 200 times cheaper than tap water. The overhead of mains water, this does not seem unreasonable.
So there is the idea: a farmer, dye company or printer gets very nearly free water – but not from the water company.
The die company cam actually such pure water from his discharg pond, and send the water, minus the dies around again. Mains water is just too dear! 1st year engineering degree strikes again.
The energy use is so small, you will not notice. A kettle uses a 5,000 W element. A washing machine a 20,000 W motor.