[oska]

Rain is essentially distilled water (evaporation from terrestrial water bodies and then condensation in the atmosphere). It picks up some contaminants in the atmosphere and some dissolved gases when it condenses but it's going to be mostly free of minerals (i.e. not be hard). So collecting rain water is one source of bulk 'distilled water'.

[bitxbitxbitcoin]

Depending on where he lives, that might actually be illegal to do.[1]

[1] https://bestlifeonline.com/illegal-collect-rainwater/