Reverse osmosis expansible pressurized permeate storage having permeate and concentrate controls

A water treatment and storage system, comprising:

• a reverse osmosis treatment unit having an untreated water input line, a bleed water output line, and a treated water output line separated from said untreated water input line and said bleed water output line by a reverse osmosis semipermeable membrane
• expandable container means having a movable portion and defining an expandable storage chamber for storing treated water,
• container valve means, connecting said storage chamber to said treated water output line of said reverse osmosis treatment unit, for permitting flow of treated water to said storage chamber when less than a predetermined quantity of treated water is stored in said storage chamber, and for terminating said flow of treated water to said storage chamber when said predetermined quantity of treated water is stored in said storage chamber, said container valve means including mechanical linkage means connected to said movable portion of said container means for providing solely mechanical control of said container valve means, and
• pressure spring means for applying a spring force to said expandable container means to maintain said stored treated water in said storage chamber under pressure.