Originally Posted by jmf143
I get it for about $0.35/gal in stores around my house. I brew 15 - 20 batches per year and use 10 gallons for each batch, of which half is my tap and half is RO. My annual cost is, at most, $35 for RO water.
That cost is not too bad, but what about the PITA cost to have to go out and get it? That's another variable that may influence a buying decision. For me, that would be a deal breaker since I don't want to go to another store and pick up big things of water.
My RO system is used for a lot more than brewing. I think my system was about $150 with a tank. I also added another 20 gal pressure tank that I picked up locally off of Craigslist.
Considering that all the components are virtually identical and are now a commodity, there is no advantage in buying a name brand or expensive system. You need 3 things: particulate filter, carbon filter, and membrane (3 stages). Anything more than those 3 stages is not really needed. Some systems have an extra particulate filter and post carbon filter. Some even have deionizing columns to get out that last little bit.
The one component that you may want to target is the membrane manufacturer. Filmtec (Dow) has a good reputation and is worth seeking. All the rest of the filters and canisters are generic and all should generally be equivalent.