Norwesco 250 Gallon Plastic Underground Water Storage Cistern Tank

The Norwesco 250-gallon underground water storage cistern is built for buried non-potable water storage where an above-ground tank won't fit the site - rural homesteads, cabins, fire-reserve supply, irrigation holding, and water-haul fill stations. Molded from white polyethylene with a ribbed underground profile, it holds 250 gallons in a compact 47-inch by 47-inch footprint and stands 56 inches tall, so it drops into a modest excavation without sprawling across your lot. It carries a 1.9 specific gravity rating, which is the structural headroom that lets it handle the load of a full water column plus burial backfill pressure. Note this is a non-potable water storage and cistern tank - confirm your end use before you order.

Will it work for your site?

Fill weight is the number that drives your install plan. Water alone in this tank runs about 2,085 pounds when full, and the tank is rated to carry contents up to 3,962 pounds - the gap between those two figures is your safety margin and the reason the 1.9 SG rating matters for a buried tank under backfill. Size your bedding and pad base to the full 2,085-pound loaded weight, not the empty shell, and plan your excavation, uniform backfill, and any anti-flotation tie-downs around the 47 x 47-inch footprint and the 56-inch height. Underground cisterns sit below grade, so confirm your water table and drainage before you dig; a high water table is the single biggest variable in a buried-tank install. For sizing across multiple tanks or matching capacity to your daily draw, run the numbers through our Tank Sizing Calculator and the Tank Sizing Guide before you commit to a hole.

Install and commissioning

Before you backfill, hydrostatic-test the tank to catch fitting leaks and watch for pad settlement - our hydrostatic test methodology guide walks the water-fill discipline and hold-time math step by step. If this cistern is feeding a rural fire-reserve setup, our fire-water reservoir design guide covers NFPA 22 sizing and cold-climate freeze protection - relevant since a buried tank gains thermal mass from the surrounding soil. For grey-water, rainwater, or HVAC condensate aggregation into a reuse-capable storage train, see our water reuse topology guide. Reference the technical drawing on this page for fitting locations and dimensional detail before you plumb, and call to confirm inlet, outlet, and lid configuration for your order - we don't want you guessing at a fitting that isn't on the page.

The mistake to avoid

The most common error on a buried cistern is treating it like an above-ground tank and skimping on bedding and backfill. This is an underground-rated tank - it needs proper bedding, uniform backfill compaction around the full footprint, and a flotation plan if your water table is high. Do not exceed the 3,962-pound rated contents limit, and do not set it in a hole without confirming the soil can support and surround it correctly. The 1.9 SG rating is your structural allowance for water plus burial loads, not a license to skip the bedding work.

This Norwesco cistern ships LTL freight, quoted live to your ZIP from the nearest of five Norwesco plants - St. Bonifacius, MN; Lancaster, OH; Shawnee, OK; Tooele, UT; or Washougal, WA. Get your freight cost with our Freight Cost Estimator, or call 866-418-1777 to confirm fittings, lead time, and the closest shipping point for your address.