305 Gallon Plastic Water Storage Tank

Where a 305 gallon tank earns its place

This is a tank for a job with a ceiling or a doorway in the way: a garden and greenhouse reserve, a backup supply for a small household on a well, a wash-down tank in a barn, rainwater off a shed roof, or water on a trailer for a remote crew. At 50 inches tall you can look into the manway standing on the ground and reach the floor with a brush, which matters when the tank gets cleaned once a year. The footprint is a 46 inch circle, and the whole circle has to sit on a flat, level, continuous surface, because a rotationally moulded floor bears on everything it touches and bridges nothing. Compacted gravel in a frame or a small slab both work; the concrete pad sizing guide covers how to size a pad for an above ground polyethylene tank. On a deck or a trailer, strap it while it is empty, because part-full water moves hard on a corner. If the tank is part of a rural fire reserve, the fire water reservoir design guide explains where a tank this size fits and how to protect it from freezing. Check the volume against the demand with the tank sizing calculator and the tank sizing guide before you commit to the size.

Openings and fittings

1. Outlet. A 2 inch polypropylene female NPT bulkhead fitting, factory installed low in the wall. A 2 inch ball valve threads straight in; put a union or a camlock after the valve so the tank can be disconnected without draining it.
2. Inlet. A 1-1/2 inch polypropylene female NPT bulkhead fitting for the fill line from a pump, a downspout filter or a float valve.
3. Manway. A 16 inch threaded vented manway on top: wide enough to fill from a hose, to drop a float switch in, and to get an arm and a brush inside.
4. Rating. 1.1 specific gravity, a maximum of 9.18 lb per gallon. That covers water and little else; most liquid fertilizers are heavier and need a tank rated 1.5 or higher. Keep the contents under 120 F.
5. Drawing. Norwesco's drawing for this tank, linked under Technical Drawing on this page, shows the exact outlet and inlet heights and the manway position.

Sizes and colours nearby

Same tank in dark green, for a yard where black stands out too much: the 305 gallon dark green vertical water tank; California buyers have the 305 gallon green California tank. A taller, narrower alternative at nearly the same volume: the 300 gallon vertical water tank. One step up: the 500 gallon green California tank. The colour swatches above the price switch between the versions of this tank.

Shipping and receiving

The tank ships LTL, 46 by 46 by 50 inches at 64 lb, from the nearest of Norwesco's plants: Fairfield, Texas; Griffin, Georgia; Hanford, California; Lancaster, Ohio; Owego, New York; Shawnee, Oklahoma; Tooele, Utah or Washougal, Washington. With eight plants, most buyers are one regional lane from a tank, and the lane is most of what the freight costs on a 64 lb shipment. The listed price is before freight; the freight cost estimator gives the cost to your ZIP, or request a written quote for a job that needs paperwork. At the tailgate, check the part number against 40702 on the bill of lading, look the shell over for transit damage, and run the water fill acceptance test before it carries anything else.

Questions before you order? Call 866-418-1777.