Norwesco 1175 Gallon Underground Water Storage Cistern Tank

What it is for

Rainwater collection, well water storage where the well cannot keep up with peak demand, and a buried reserve for a home or outbuilding where an above ground tank would freeze or be in the way. Below the frost line the water stays liquid through winter and cool through summer, and nothing sits in the yard. The same tank is used as a fire water reserve on rural sites; our guide to fire water reservoir design for rural and remote sites covers sizing and freeze protection. If the tank feeds a grey water or reuse system, the water reuse tank layout guide is worth reading before you plumb it. For the volume, use the tank sizing calculator and tank sizing guide.

Openings, risers and what to check before you buy

1. Manways. Two 20 inch gasketed manways. One takes the pump and float, the other gives you a second access point for inspection and cleaning. The gasket keeps surface water and soil out of the tank.
2. Risers and extensions. Norwesco makes a kit for each manway, ordered in pairs: 6 inch extension N-63832, 15 inch extension N-63833, 24 inch extension N-63834, a 23 inch riser with a 12 inch lid N-63831, and a 36 inch riser with a 6 inch lid N-63830. Decide your burial depth first, then tell us; we put the kits on the same order.
3. Inlet and outlet. No fittings are listed on this tank. Tell us where the inlet and the pump line enter and what size, and we confirm what ships on the tank and what to add before it leaves the plant.
4. The hole. The tank is 127 by 60 inches at the body and 51 inches tall. Excavate wide enough to compact bedding and backfill around it evenly, on a firm, level base with no rocks under the tank.
5. Burial depth and traffic. Norwesco's installation instructions set the maximum cover and whether any vehicle load is allowed over the tank. Follow them, not a rule of thumb, and never park on a buried polyethylene tank.

Norwesco's drawing for this tank is linked on this page under Technical Drawing. It shows the manway positions, the rib pattern and the outside dimensions you need for the excavation plan.

Installing it

Set the tank on compacted bedding, check it for level along its length, and fill it with water as you backfill so the water inside balances the soil pressure outside. Backfill in lifts and compact each one; a void under a rib is where a buried tank fails years later. Before the backfill covers the fittings, run water through every connection and look for weeps. Our guide to hydrostatic acceptance testing for new tank installs gives the fill and hold procedure. Bring the manways to grade with the risers so the lids sit just above finished ground and surface water runs away from them.

Shipping and receiving

The tank ships LTL freight, NMFC 156600-02, from Norwesco's Owego, New York plant, 127 by 60 by 51 inches and 329 lb on the truck. Risers ordered with the tank travel with it. The listed price is before freight; the freight cost estimator gives the lane cost to your ZIP, or request a written quote if the job needs paperwork. At the tailgate, check the part number against 40199 on the bill of lading and look over the ribs and both manway flanges for transit damage before the driver leaves; a buried tank is a hard one to swap later.

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