4995 Gallon Plastic Water Storage Tank: Complete Buyer's Guide
The 4,995-gallon black water tank is large potable storage in a wide, low form — 142 inches across and 89 inches tall, holding better than twenty-three tons of water full. The black wall blocks light to keep algae out of stored water, and the FDA-compliant resin keeps it safe to drink.
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
Just under five thousand gallons is a substantial water reserve — enough to carry a household or small operation through extended outages, supplement a weak well, or anchor a livestock or irrigation supply. At nearly twelve feet across and just over seven feet tall, this tank is broad and low, a stable cylinder that distributes its considerable full weight over a large base and gravity-drains cleanly.
Norwesco rotomolds it as one seamless piece of virgin linear polyethylene, no seam or weld anywhere, with FDA-compliant resin for potable and food-grade contact. For a large drinking-water reserve, the seamless build means no fabricated joint to leak under load and no crevice to harbor biofilm. The wall is rated to a 1.1 specific gravity, covering water comfortably with margin.
The black pigment is the practical choice for stored water: it's fully opaque, so it blocks the light algae needs to grow, keeping a large volume clearer with less frequent cleaning, and black is among the most UV-durable polyethylene colors for long open-air life. Empty, the tank weighs 758 pounds; filled with water it loads the pad with roughly 46,582 pounds — over twenty-three tons across the 142-inch footprint, which the wide base spreads broadly. Maximum service temperature is 120°F.
Plumbing is ready out of the box: a 2-inch NPT outlet for strong flow and a 1.5-inch NPT inlet fitting included for your fill line. The 22-inch lid provides large fill, vent, and inspection access. Norwesco's 3-year warranty applies, and the tank ships via dedicated freight carrier given its size — contact us for delivery timeline and site access.
Technical Drawing
Official Norwesco technical drawing — 4995 Gallon Plastic Water Storage Tank
Key Features and Specifications
- 4,995-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
- 89" tall x 142" diameter — compact vertical footprint
- 758 lbs empty, approximately 46,582 lbs when full at rated specific gravity
- 2" NPT outlet fitting — factory installed and leak-tested
- 1.5" NPT inlet fitting included
- 22" 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
- Install on a level, compacted surface. Ensure adequate clearance above for lid access and around the perimeter for plumbing connections and visual inspection
- Ships via dedicated freight carrier due to oversized dimensions — contact us for delivery timeline and site access requirements
Installation and Setup Guide
A twenty-three-ton full water tank needs a real foundation, but the wide low geometry takes the drama out of the rest — low center of gravity, broad load spread, no platform gymnastics. Focus on the pad and the freight set.
Site Preparation
Provide an engineered base for the full load across the 142-inch footprint — a substantial reinforced concrete slab or an engineered compacted pad, level within an inch across the diameter. The wide footprint spreads twenty-three tons well, but the slab and subgrade still must be specified to carry it without uneven settlement. Pick a well-drained site, and leave generous perimeter room for the freight set, plumbing, and inspection.
Placement and Connections
Connect the included 1.5-inch inlet to your fill source and the 2-inch outlet to your pump or gravity line. Use flexible connections at both fittings to absorb the tank's thermal movement; a rigid line on a large tank will eventually crack or loosen. The 22-inch lid sits about seven feet up — plan ladder or platform access. Support all piping independently so its weight never bears on the tank fittings.
Venting
Fit a screened vent in the 22-inch lid sized to your peak fill and draw flow. A nearly-five-thousand-gallon tank moves a large air volume, and an undersized vent can pull vacuum during a fast draw. The screen keeps insects, debris, and small animals out of the potable reserve while letting the tank breathe — non-negotiable on a drinking-water tank.
Maintenance and Long-Term Care
Maintaining a large water tank is about protecting the structure and keeping a big reserve drinkable. The black wall handles algae; the rest is scheduled inspection and periodic sanitizing.
Quarterly Inspection Checklist
- Water clarity: Look through the 22-inch lid for cloudiness, sediment, or growth. The opaque black wall blocks light, so any growth usually means light or contaminants are entering via a compromised screen or seal — find and fix it.
- Base and settlement: Walk the 142-inch perimeter for even seating — no low edge, gap, or washout. Differential settlement is the chief structural concern for a wide heavy tank.
- Fittings: Check the 2-inch outlet and 1.5-inch inlet for weeping; even a slow seep is a meaningful loss at this volume.
- Vent screen: Confirm the vent is open and the screen is intact.
Cleaning and Sanitizing
Sanitize at least annually. Drain the tank, scrub the interior through the 22-inch lid (observe confined-space precautions for any entry), then disinfect the walls and fittings with a chlorine solution — roughly a quarter cup of unscented household bleach per 15 gallons used — let it dwell a couple of hours, drain, and flush with fresh water until the chlorine odor is gone. This clears biofilm and keeps a large reserve safe to drink.
UV and Weather
Black polyethylene is highly UV-durable, so this tank handles full sun well. Inspect exposed faces yearly for chalking. In hot climates the dark wall absorbs heat and a large volume warms slowly; if water temperature matters, partial shade helps without giving up the black wall's algae control.
Alternatives and Comparisons
For a nearly-five-thousand-gallon reserve, weigh color and configuration:
Black versus green or a lighter water tank: black and green both block light to control algae and resist UV; black is the most durable color and the usual pick where appearance is secondary to performance. A translucent tank shows the level but admits algae-feeding light — not the right trade for a large stored supply.
Single large tank versus a pair: one 4,995-gallon tank means a single foundation and fewer fittings; two smaller tanks let you keep half the reserve in service while cleaning the other. For critical water security, redundancy can be worth the extra foundation.
Other 4995-Gallon Options
Frequently Asked Questions
How long will the 4995 Gallon Plastic Water Storage Tank last?
Fifteen to twenty years is realistic with an engineered, level base and normal use. Black polyethylene is among the most UV-durable colors, and the seamless wall has no joints to fail, so a large water tank generally delivers excellent service life. Foundation quality and routine sanitizing carry it to the top of the range.
What chemicals can I store in this tank?
This is a potable water tank — FDA compliant for drinking water and food-grade liquids, rated to a 1.1 specific gravity for water and benign aqueous solutions up to about 9.2 pounds per gallon. It is not for aggressive chemicals, fuels, or solvents; for those, choose a higher-specific-gravity tank verified for the chemistry. Keep this one for water and water-based use.
What kind of foundation does a 4995-gallon tank need?
It needs an engineered base — a substantial reinforced slab or engineered compacted pad — sized for roughly 46,582 pounds across the 142-inch footprint, level within about an inch on uniformly compacted subgrade. The wide base spreads twenty-three tons, but the foundation must still be specified to carry it without uneven settlement.
Does this tank come with a warranty?
Yes — Norwesco's 3-year warranty covers defects in materials and workmanship. It excludes uneven or inadequate foundations, freezing damage, and impact damage. Keep documentation of the engineered pad for any claim at this scale.
Can I install this tank underground?
No — this is an above-ground water tank not engineered for burial; soil pressure would deform the wall, and a tank this size is impractical to bury anyway. For below-grade water storage, use a purpose-built underground cistern designed for soil load.
Buying Considerations
Plan the project before the purchase. Confirm an engineered base for twenty-three-plus tons and a well-drained site for the twelve-foot footprint. The included 2-inch outlet and 1.5-inch inlet make it ready to integrate into a water system. If hard freezes occur where you are, protect the plumbing — a large reserve resists freezing solid, but exposed fittings still need attention. This ships by dedicated freight carrier; call us to coordinate delivery and confirm equipment and access for setting the 758-pound shell.
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