The B526 gives you 16 gallons in 26 x 14 x 11 inches - weekender scale. It is the size that covers two people and two days on the hook without surrendering a whole locker, and at 19 lb empty it goes into the boat through the companionway without a second pair of hands.
Ronco molds the B-series as dual-role blanks, and the B526 is a popular size in both roles. As a fresh tank the resin is FDA approved for potable water; as a holding tank the same molding takes gray or black service. What decides it is the fitting order: you mark the locations, Ronco spin-welds or thread-installs to those marks, and the tank arrives ready to plumb for the job you chose. The drawing below is printable for exactly this purpose - mark it up, then commit the layout in the on-page fitting planner.
Budget about 133 lb for the tank full. That is within reach of a plywood shelf and a pair of straps, but mount it so the bottom is carried across its area, not suspended by the flange line. Tustin, California production, on tooling from a shop molding marine tanks since 1974.
The whole size run lives in our boat tank category; land-side equivalents are under RV water tanks, and the maker's full catalog is on the Ronco Plastics hub. OneSource Plastics is an authorized Ronco Plastics dealer.
Technical drawing: download the Ronco Plastics B526 dimensional drawing - print it to plan your install and mark exactly where you want fittings located; Ronco installs spin-weld or threaded fittings to your marked spec.
