400 Gallon Green Doorway Water Tank

The 400 Gallon Green Doorway Water Tank fits through standard 32-inch doorways for indoor storage without structural modification. The molded-in center gap ties the two largest walls together, providing free-standing structural integrity — no frame, bolts, or anchoring required. At 400 gallons, this is serious indoor capacity for commercial hydroponics, water treatment chemical storage, or institutional emergency preparedness. Norwesco #44361.

Applications & Use Cases

Potable Water Storage

This tank stores 400 gallons of drinking water using FDA-approved resin (21 CFR 177.1520). At FEMA's recommended 1 gallon per person per day, this provides 400 days for one person or 100 days for a family of four. For extended emergencies, account for cooking, sanitation, and pet needs — plan 2-3 gallons per person per day for total water use.

Livestock Watering

Daily water requirements: beef cattle 8-12 gal, lactating dairy cows 30-50 gal, horses 8-10 gal, sheep/goats 2-3 gal, poultry 0.08 gal per bird. This 400-gallon tank supplies approximately 33 beef cattle, 40 horses, or 4,800 chickens for one day. For continuous supply, pair with an automatic float valve and pressure system.

Indoor Installation Scenarios

• Basement emergency water: Position near the water heater or utility area. Connect to house plumbing via a transfer pump for pressurized distribution during outages.
• Commercial hydroponics: Nutrient solution reservoir for indoor grow operations. The opaque walls prevent algae in nutrient solutions.
• Water treatment day tank: Chlorine, acid, or polymer day tank in municipal treatment plant mechanical rooms where access is through standard doors.
• Institutional preparedness: Schools, hospitals, data centers, and commercial buildings for emergency water or process chemical backup.

Weight Calculator

Water weighs 8.34 lbs/gallon. Multiply by specific gravity for other liquids. Empty weight: 183 lbs.

Installation Guide

Foundation Requirements

At 3,853 lbs full (0.0 PSI on the base), this tank requires a level, compacted gravel pad at minimum. Recommended: 4-6 inches of compacted 3/4" crushed stone extending 6" beyond the tank perimeter on all sides. A reinforced concrete pad is preferred for permanent installations. Surface must be level to within 1/4" across the full diameter.

Placement & Handling

Use a forklift for placement. Lift from below the tank — never grab by the collar, lid, or fittings (they are not structural). Use fork extensions if the tank diameter exceeds your fork spread.

Plumbing Connection (Critical)

From the official Norwesco installation guide: "Rigid piping must not be connected directly to a tank — a flexible connection of some sort is required." Polyethylene tanks expand and contract with temperature changes and fill level. A flexible hose connection absorbs this movement and prevents stress fractures at the fitting boss. This single precaution significantly extends tank life.

• Outlet: Use reinforced flexible hose between the tank fitting and your valve or pipe. A cam-lock coupler provides quick disconnect.
• Overflow: Water tanks include an overflow fitting near the top. Pipe to a safe discharge point — never cap it.
• Venting: The standard vented lid provides atmospheric venting. If you modify or seal the lid, install a separate vent to prevent vacuum/pressure buildup.
• Fitting material: Standard: glass-filled polypropylene with EPDM gaskets. For chemical service: request Viton gaskets or stainless steel fittings from Norwesco (800-328-3420).

Material Science & Construction

Resin and Material

Manufactured from virgin linear high-density polyethylene (HDPE) specifically formulated for rotational molding. The resin includes compounded UV stabilizers for long-term outdoor durability, antioxidants for processing stability, and meets FDA 21 CFR 177.1520 requirements for food-contact applications where applicable. This is purpose-engineered tank resin — not commodity plastic.

Rotational Molding Process

Every Norwesco tank is formed as a single piece through rotational molding — the resin is loaded into a heated mold that rotates biaxially, distributing molten plastic uniformly across all surfaces. The result is a seamless tank wall with no welds, joints, or stress concentrations. This process achieves the highest strength-to-weight ratio in the tank industry. Because there are no seams, there are no inherent weak points where leaks or cracks can initiate.

UV-15 Stabilization

The UV-15 stabilizer is compounded directly into the polyethylene resin during manufacturing — it is part of the molecular structure, not a surface coating that wears off. This provides best-in-class UV degradation resistance for the entire service life of the tank. Tanks made from unstabilized resin (common in imported or recycled-material tanks) begin visibly degrading within 2-3 years of outdoor exposure.

FDA Compliance

Norwesco's resin (Norwesco-specified HDPE resin) is certified to comply with FDA 21 CFR 177.1520 (Olefin polymers), paragraph (c)3.1a. Per the official regulatory declaration dated June 2019:

• May be used as articles intended for use in contact with food
• Food contact under Conditions of Use D through G (Table 2 of 21 CFR 176.170(c))
• Temperatures not in excess of 150°F for food contact applications
• Finished article must be at least 2 US gallons for fatty food contact
• Produced under good manufacturing practice per 21 CFR § 174.5(a)

Shipping & Manufacturing

Manufactured at Norwesco plants in Washougal, WA, Hanford, CA. Ships from the plant closest to your delivery address.

Norwesco operates 15 US plants plus 2 in Canada �� this decentralized structure means lower freight cost and faster delivery than competitors with centralized warehouses.

LTL Freight: Ships via flatbed. Forklift or equipment required for offloading. Call (866) 418-1777 for freight quote.

Frequently Asked Questions