Darrell, could you quote me section in the uniform plumbing code that requires 18 gpm flow rate? Thanks. Unless I see it in writing, I disagree. 18 gpm would take a larger pipe size than the standard 3/4" or 1" put in most homes around here under the upc. The sears softners with 8 or 9 or 10 gpm work just fine. Sears or rainsoft doesn't fit your 18gpm requirements, what brand are you selling. I think Pam needs to look at her own plumbing system size and pressure to see what her flow rate is. nuff said for now.