550 Gallon Plastic Water Storage Tank: Complete Buyer's Guide
A 550-gallon black potable-water tank in a low, broad 44-by-67-inch body — knee-high, hard to tip, and easy to fill without a step. FDA-approved Norwesco polyethylene, pigmented black to stop light and algae, with a 2-inch outlet and 1.5-inch inlet already installed for household backup, livestock, or small-property water supply.
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
The 550 Gallon Plastic Water Storage Tank is the practical mid-size potable tank for a homestead, a livestock setup, or a dependable household water backup. Its squat 44-by-67-inch shape sits low and stable — you fill and check it through the 16-inch lid standing flat-footed, and the wide base keeps it planted even when partly full.
The opaque black wall is its algae defense, blocking the light that would cloud water in a translucent tank and keeping the 550-gallon reserve clearer between turnovers. Like the other black water tanks it arrives ready to plumb, with a factory 2-inch outlet near the base and an included 1.5-inch inlet up top, and the 16-inch lid accepts a float valve, level sensor, or small pump.
The empty shell is 94 pounds — a two-person lift into place. Filled with water at the rated 1.1 specific gravity, about 9.2 pounds per gallon, the tank reaches roughly 5,140 pounds, around two and a half tons on the broad 24.5-square-foot base. The low, wide form makes that load very stable.
The one-piece molding has no joint to leak, the tank meets FDA potable and food-grade approval, and Norwesco covers it for 3 years. We inspect each one before it leaves our dock.
Technical Drawing
Official Norwesco technical drawing — 550 Gallon Plastic Water Storage Tank
Key Features and Specifications
- 550-gallon capacity — sized for safe potable water storage
- Constructed from virgin linear polyethylene (HDPE) with 1.1 specific gravity rating — handles liquids up to 9.2 lbs/gal
- 44" tall x 67" diameter — compact vertical footprint
- 94 lbs empty, approximately 5,140 lbs when full at rated specific gravity
- 2" NPT outlet fitting — factory installed and leak-tested
- 1.5" NPT inlet fitting included
- 16" lid opening for fill, venting, and interior access
- FDA approved for potable water and food-grade liquid contact
- 3 Year Warranty from Norwesco against manufacturing defects
- UV-resistant black pigmentation provides maximum outdoor durability and inhibits algae growth in stored liquids
- 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 550 water tank is among the easiest to install thanks to its low, stable shape, and the added focus for a potable vessel is sanitary connections and protecting the water from contamination.
Site Preparation
Set it on a firm, flat surface that fully supports the 67-inch base — a slab, a paver bed, or a compacted pad. Level it within a quarter inch so the squat tank loads its base evenly, and clear away grit and sharp objects. Site it so runoff drains away from the lid and connections, keeping the water supply protected.
Placement and Connections
Take draw from the 2-inch outlet and fill through the 1.5-inch inlet, with potable-rated NSF PVC or food-grade fittings and a flexible section before any hard pipe. Fit a screened, insect-proof vent in the lid and keep the fill protected. About two feet of clearance is enough for inspection and service.
Venting
The tank must breathe as water moves in and out while keeping insects and debris out of the potable supply. A screened lid vent sized to your fill and draw rates handles both and prevents the wide top from drawing a vacuum.
Maintenance and Long-Term Care
Routine care keeps the water safe to drink, and a 550-gallon reserve turns over often enough on most properties to stay fresh with minimal effort.
Quarterly Inspection Checklist
- Water quality: Look for cloudiness, sediment, or odor that points to stagnation or contamination.
- Wall and base: Look for any bulge or a flat spot at the base and confirm the pad stays level under the wide footprint.
- Fittings: Feel the 2-inch outlet and 1.5-inch inlet for any weep and give a hand-snug if needed.
- Vent and lid: Make sure the screened vent stays intact and the lid keeps insects and dirt out.
Cleaning
Drain and sanitize the tank at least once a year. After clearing sediment, sanitize with a chlorine solution at about a quarter cup of unscented household bleach per fifteen gallons, let it contact all surfaces for a couple of hours, then drain and flush with fresh water until no chlorine odor remains. Refill with clean potable water, and turn the stored water over regularly to keep it fresh.
UV and Weather Protection
The black pigment serves as both UV protection and algae defense, giving the tank strong outdoor durability. In freezing climates, protect exposed plumbing and avoid letting a full tank freeze solid, since expanding ice can stress even a sound shell.
Alternatives and Comparisons
This low, wide 550 black water tank is the stable, easy-access choice for a mid-size potable reserve. A white 550 liquid-storage tank shares the dimensions but is built for chemicals at 1.5 specific gravity and is not for drinking water — choose this black tank for water. For more reserve, the 1,550 or 2,500 black water tanks step up; for less, the 305 black tank serves. Throughout, water belongs in black to fight algae, chemicals in white at the heavier rating.
Frequently Asked Questions
How long will the 550 Gallon Plastic Water Storage Tank last?
On a level base with routine sanitizing, fifteen to twenty years of dependable drinking-water service is realistic. The seamless mold has no joints to fail, and the black pigment provides UV protection and algae resistance. What typically shortens its life is a poor foundation, a full tank left to freeze, or impact — chemical attack is not an issue with clean water.
What chemicals can I store in this tank?
Purpose-built and FDA-approved for drinking water and food-grade liquids, that is its proper use. At a 1.1 specific-gravity rating, it is not built for the heavier ag and industrial chemicals that white 1.5-SG liquid-storage tanks are made for. For chemicals, choose a white liquid-storage tank rated for them.
What kind of foundation does a 550-gallon tank need?
A full load is about 5,140 pounds over the 67-inch base. A solid, level surface — slab, paver bed, or compacted pad — that carries the full diameter will do. Because the tank is short and wide, keep the surface flat within a quarter inch, and grade the area so runoff drains away from the connections to protect the water.
Does this tank come with a warranty?
Yes. Norwesco backs it three years against defects in materials and workmanship, from molding flaws to fitting faults. Excluded are freeze damage to a full tank, foundation faults, and impact. Keep your sales receipt and installation pictures on record for claims.
Can I install this tank underground?
No. It is an above-ground water tank whose flat walls would buckle under the soil and groundwater pressure of burial. Underground potable storage calls for a cistern engineered with ribbed, reinforced walls.
Buying Considerations
Run three checks before ordering this water tank. First, the footprint — the squat 44-by-67-inch shape wants ground width but little height and stays very stable. Second, plumbing — confirm the included 2-inch outlet and 1.5-inch inlet suit your fill-and-draw setup with potable-rated connections. Third, delivery — it moves palletized by LTL and a lift gate makes unloading easy. Call us to arrange delivery.
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