I ran an RO/DI line from my second bathroom, through the attic, across the catwalk, and into my detatched garage so I could fill my trash can for mixing water. I bought a 100 foot line and used every inch of it. I did upgrade to a 3/8" line right at the RO unit, but it worked fine and I used no pump. I did have a 3 gallon bladder tank in line, but once that drained the pressure was only coming from the water flow through the membrane. Yeah, it's a bit more back pressure on the unit, but I never had an issue from it.