600 Gallon Doorway Water Tank (Ribbed): Complete Buyer's Guide
The 600-gallon ribbed doorway water tank combines narrow-access storage with a ribbed wall for added structural rigidity — 58 inches long, 35 inches wide, and 83 inches tall. It passes a standard doorway, holds 600 gallons of FDA-compliant potable water, and uses molded-in ribs to stiffen the elongated body against the bulging that tall narrow tanks can be prone to.
Specifications at a Glance
Every figure below is pulled straight from the live product record for this exact tank — the same data on the product page, so what you read here and what you buy never disagree.
Standards & Materials
- ASTM D1998 — Standard Specification for Polyethylene Upright Storage Tanks. Governs wall-thickness and hydrostatic design for vertical rotomolded poly tanks of this class.
- FDA 21 CFR 177.1520 — Olefin polymers. The food-contact regulation the FDA-grade resin in this tank is compounded to meet.
- Specific gravity rating 1.1 — the tank is engineered for liquids up to 1.1× the density of water (water is about 8.34 lb/gal). Confirm your fluid’s SG before storage.
Product Overview
This 600-gallon doorway tank adds a feature worth understanding: a ribbed wall. Doorway tanks trade the inherently strong cylinder shape for an elongated, flatter-sided form to fit through openings, and flatter walls want to bulge under a tall water column. The molded-in ribs answer that — they stiffen the wall the way corrugations stiffen sheet metal, letting the tank hold 600 gallons in a doorway-friendly 35-inch width without flexing. It's the structural refinement that makes a tank this size practical in the doorway format.
Norwesco rotomolds it as a single seamless piece of virgin linear polyethylene with FDA-compliant resin for potable and food-grade contact — ribs and all formed in one shot, with no joint to leak and no crevice to harbor biofilm. The wall is rated to a 1.1 specific gravity, matched to water storage. At 58 inches long, 35 inches wide, and 83 inches tall, it packs 600 gallons into a profile that clears a standard 36-inch door on its narrow dimension.
The translucent white wall lets you read the water level by eye between the ribs and reflects light to keep contents cooler. Empty, the tank weighs 363 pounds — the ribbing adds material and rigidity, so it's heavier than a smooth tank of similar volume, which is part of what makes it sturdy. Filled with water it carries roughly 5,867 pounds on its 58-by-35-inch footprint, a load the supporting floor must handle. Maximum service temperature is 120°F.
The 16-inch lid serves fill, vent, and inspection. As with other doorway tanks, plan your fill and outlet connections to suit your indoor plumbing and the tank's end geometry. Norwesco's 3-year warranty applies, and the tank ships LTL freight on a pallet, with residential delivery and liftgate available.
Technical Drawing
Official Norwesco technical drawing — 600 Gallon Doorway Water Tank (Ribbed)
Key Features and Specifications
- 600-gallon capacity — sized for tight-access indoor liquid storage
- Constructed from virgin linear polyethylene (HDPE) with 1.1 specific gravity rating — handles liquids up to 9.2 lbs/gal
- 58" long x 35" wide x 83" tall
- 363 lbs empty, approximately 5,867 lbs when full at rated specific gravity
- 16" lid opening for fill, venting, and interior access
- FDA approved for potable water and food-grade liquid contact
- Translucent white walls allow visual level monitoring without opening the tank and reflect sunlight to keep contents cooler
- Rated for continuous service up to 120 F / 48 C
- Seamless one-piece rotational molding — no seams, no welds, no leak points
- Manufactured by Norwesco — a leading name in rotomolded polyethylene tanks
- Place on a firm, level surface free of rocks or sharp objects that could damage the tank bottom. Ensure adequate ventilation if stored chemicals produce vapors
- Ships via LTL freight — allow 2-3 weeks for delivery. Lift gate and residential delivery available at additional cost
Installation and Setup Guide
The ribbed doorway tank installs on the same principles as any doorway tank — get it in, confirm the floor, plumb the water — with the ribbing giving you a bit more confidence against wall flex once it's filled.
Getting It In and Floor Loading
Measure your route against the 35-inch width, 83-inch height, and 58-inch length. The narrow width clears a standard door, but the 83-inch height is substantial — watch overhead clearance and stairwell turns, since you may need to tip it to maneuver. The 363-pound empty weight is on the heavier side for a doorway tank thanks to the ribbing, so plan for two or more people or a cart. Confirm the floor carries roughly 5,867 pounds full before you fill, especially on framed or upper floors.
Placement and Connections
Set the tank on a flat, level surface free of debris — the ribs stiffen the wall, but the base still needs full, even support. Connect your fill line and outlet to your indoor plumbing, using flexible couplings to absorb thermal movement. Route an overflow so any escaping water drains safely rather than into the room. Keep the supported base continuous; ribs help the walls, not the floor of the tank.
Venting
Fit a screened vent in the 16-inch lid sized to your fill and draw rate. Even a ribbed, stiffened tank must breathe — vacuum from a sealed draw can still distort it. The screen keeps debris and insects out of the potable water, and indoors you should ensure the vent reaches adequate air in an enclosed space.
Maintenance and Long-Term Care
The ribbed tank's maintenance mirrors other indoor water tanks, with the ribs giving the walls extra resilience to inspect against.
Quarterly Inspection Checklist
- Wall and ribs: Check the wall and the ribbed sections through the translucent material for any unusual bulging between ribs or stress at a rib — the ribbing should keep the wall flat, so distortion is a sign of a vent or support problem.
- Water clarity: Read level and clarity through the wall and lid; indoors, cloudiness usually means stale water needing a refresh.
- Fittings and floor: Inspect connections for weeping and confirm the floor under the tank is dry and sound.
- Vent screen and base: Verify the vent is clear and the screen intact, and that the tank sits level on full support.
Cleaning and Sanitizing
Sanitize at least annually. Drain, scrub the interior through the 16-inch lid — the ribs are external, so the interior wall is smooth to clean — then disinfect with a chlorine solution of about a quarter cup of unscented household bleach per 15 gallons used, let it stand a couple of hours, drain, and flush with fresh water until no chlorine odor remains.
Indoor Considerations
Indoors the tank is spared UV, so no chalking. Keep the space within the 120°F service limit and protect against freezing in unheated areas. The ribbing adds rigidity but is not a substitute for freeze protection — a frozen full tank can still be damaged. Plan drainage around the tank for leak protection.
Alternatives and Comparisons
The ribbing is the differentiator, so compare on structure and access:
Ribbed versus smooth-wall doorway tank: the ribbed wall resists bulging under a tall water column, which is why it's used at larger doorway capacities. A smooth-wall doorway tank is lighter and fine at smaller sizes; at 600 gallons in a narrow profile, the ribs earn their extra weight by keeping the wall stable. If you want a sturdy large doorway tank, the ribbed version is the more confident choice.
Doorway versus standard cylinder: choose the doorway format when narrow access requires it; a standard vertical is cheaper per gallon where you can place it. The doorway design buys access; the ribbing buys wall stability at this capacity.
Other 600-Gallon Options
Frequently Asked Questions
How long will the 600 Gallon Doorway Water Tank (Ribbed) last?
Fifteen to twenty years is realistic, helped by indoor placement and the rib-stiffened wall, which resists the flex that ages a flat-walled tank. With a level base and routine sanitizing, the seamless rotomolded construction reaches the upper end of that range.
What chemicals can I store in this tank?
This is a potable water tank — FDA compliant for drinking water and food-grade liquids and rated to a 1.1 specific gravity for water and benign aqueous solutions. Doorway tanks are intended for water and water-based storage; never use one for fuels, solvents, or flammables, and confirm compatibility before storing any chemical.
What kind of foundation does a 600-gallon tank need?
A full tank is roughly 5,867 pounds on the 58-by-35-inch footprint — verify a framed or upper floor carries it before filling. A flat, level surface free of debris is required, with continuous support under the base; the ribs stiffen the walls, but the floor still needs even, full support.
Does this tank come with a warranty?
Yes — Norwesco's 3-year warranty covers defects in materials and workmanship. It excludes uneven or improper installation, freezing damage, and impact damage. Keep documentation of a level install for any claim.
Can I install this tank underground?
No — this is an above-ground tank designed for interior placement, not burial; the ribbing stiffens it against a water column, not against soil pressure, which would still deform it. For below-grade water storage, use a purpose-built underground cistern designed for soil load.
Buying Considerations
If you need a large doorway tank that won't flex, the ribbed 600-gallon is the one to choose — the ribs are there specifically to keep the wall stable under the water column. Measure your route against the 35-inch width, 83-inch height, and 58-inch length, and plan for the heavier 363-pound empty weight when moving it in. Confirm the floor carries roughly 5,867 pounds full, plan freeze protection if unheated, and provide a level base. It ships LTL on a pallet with residential and liftgate delivery available.
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