3M 3MRO501-01 Pro Reverse Osmosis Drinking Water Filtration System

Great RO unit for under-sink application

The quarter-turn filter and membrane cartridges are very handy for an under-sink application. The integrated booster pump is also a nice feature; and it really helps with space required and ease of installation of the unit (if your application requires a booster pump). Here are a few notes from installation: 1) the instructions are complete, but not very user-friendly; this is a simple system to install - just take your time and read carefully; 2) as you face the front of the assembly, the sediment pre-filter is in the back on the left side; unless you install the assembly near the front and on the left side of the sink cabinet, it may be difficult to access this cartridge for replacement (unless you've left enough extra tubing to remove the assembly from the cabinet); 3) the fitting provided for tying into the cold water line has limited applicability; I purchased a 3/8"X3/8"X1/4" angle stop valve (Fresh Water Systems sells a couple of different brands) which worked great; 4) the only post-installation leak I had was at the pre-installed drain fitting for the membrane cartridge; it's a specialty fitting with fine threads which had been cross-threaded; 5) the membrane requires a 24-hour pre-service flush - so plan accordingly. All in all a very good system for my application.