I’ve just purchased more resin and pre filters that’s me set to make 1000s upon 1000s of litres of water for the foreseeable and when you break that cost down over 6 months that’s pennies per 100 litres don’t know about 1 litre lol people that use this way to get their water everyday want either their heads testing or they need to save that money and move house-flat.
If you had a ground floor flat with off road parking you could make water I know this isn’t possible for everyone but you can rent a small 8x8 shed to make water in somewhere.