Firstly I'd like to say how fantastic this site is. I'm wanting to start my own pure water window cleaning company. I've spent the last few days doing lots of research about making pure water. My head is ready to explode. I understand the process of making the water, however, i'm still unsure about what equipment is best to buy. Firstly, I live in a very hard water area. I'm going to make the water in my garage using an outside tap, then transfer the water into smaller containers and take them to customers houses, hopefully using a trolley. I am hoping to connect a hose from my outside tap, to the RO unit, then a hose from the RO unit to a water butt. I believe i have good outside water pressure, but not sure of the exact pressure and how strong it has to be for the RO unit. I've read in lots of places, something about filtering the waste water to make even more pure water, is this true? as surely the waste water in no good?? I am on a water meter, and also dont like the idea of wasting lots of water! Also does anyone know what the average water to waste ratio is?? As i've read some people have alot of waste and just a slow trickle of pure. I've read on a lot of forums that I should bother with 200gdp as they are very slow. And should go straight for a 450. What do u think. As you can see, i am a complete novice, and any help you can give will be greatly appriciated. I'd also like advice on best RO units to buy, trolleys, poles and brushes, but not to break the bank Thank you so much for your time reading this and sorry for such a long post!!