40 Gallon Plastic Water Storage Tank: Complete Buyer's Guide
40 Gallon Plastic Water Storage Tank from Norwesco.
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 1.0 — the tank is engineered for liquids up to 1.0× the density of water (water is about 8.34 lb/gal). Confirm your fluid’s SG before storage.
Installation and Setup Guide
Forty gallons is the smallest reserve in this lineup, and that scale flips the install priorities: weight is almost a non-issue — a full tank is well under 400 pounds — so the real questions are where it sits, how it is secured, and how cleanly it plumbs into whatever it feeds. Think of this as a point-of-use or backup tank rather than a bulk store, and place it accordingly.
Site Preparation
A small, level surface is plenty: a paver, a sturdy shelf rated for the load, or a short stretch of flat concrete. The one rule that still applies from the big tanks is flatness — even 40 gallons sitting cocked puts uneven stress on the wall — so shim the base true. If it lives on a platform or anywhere it could be knocked, fasten or strap it; a light tank is easy to bump out of place.
Placement and Connections
Keep the plumbing simple and short. Run the discharge off the lowest fitting with a flexible connector for the first segment so the tank can shift slightly as it fills without straining the bulkhead. Hand-tighten every threaded fitting and add only a quarter turn; the small fittings on a tank this size strip or crack even more easily than the big ones if you reach for a wrench.
Venting
Small as it is, the tank still needs to breathe. Leave the lid vent or fill opening clear so air can move in as you draw water out and out as you fill — a sealed small tank can deform under a brisk pump-down just as a large one can. A simple screen keeps insects out of the opening without restricting that airflow.
Maintenance and Long-Term Care
A 40-gallon water tank is the easiest in the catalog to keep clean, precisely because it is small enough to drain, scrub, and refill in a single short session. The flip side is that a small reserve turns over slowly if it is a backup, so freshness — not structure — is what the routine below protects.
Quarterly Inspection Checklist
- Quick visual: Glance over the whole tank for any swelling, cracking, or weeping at the fitting; on a small tank you can inspect every surface in seconds.
- Fitting check: Hand-snug the outlet, taking extra care since small poly fittings are the easiest to over-torque.
- Mount check: If it sits on a shelf or platform, confirm the support is sound and the tank has not shifted.
- Opening clear: Make sure the vent or lid opening is unobstructed so the tank breathes as it fills and empties.
Cleaning
Because it is small, drain and clean this tank as often as the water sits — at least annually for an active tank, more for a standby reserve. Empty it fully, rinse, then sanitize with unscented bleach scaled to the 40-gallon volume (a couple of tablespoons), hold it briefly, and flush until the chlorine smell is gone. The whole job takes a few minutes, so there is no excuse to let the water go stale.
UV and Weather Protection
Even a small water tank benefits from UV protection, and keeping a 40-gallon tank out of direct, all-day sun is trivial — set it under a roofline, inside a pump house, or behind a screen. If it must live outdoors, check the sun-facing side yearly and consider relocating it into shade, which is effortless at this weight.
Alternatives and Comparisons
Forty gallons is a point-of-use or backup reserve, not a bulk supply — useful where space and need are both small. If you find yourself refilling constantly, the larger tanks below carry far more water without much more floor space. Compare the sizes to match your real draw rather than under-buying.
Other -Gallon Options
Frequently Asked Questions
How long will the 40 Gallon Plastic Water Storage Tank last?
A 40-gallon tank, kept on a flat support, filled with water, and sanitized regularly, easily lasts well over a decade — often longer, since it is small enough to keep out of harsh sun and easy to maintain. Its molded wall has no seams to fail; the main thing that ages a small tank early is being left in full sun or filled with the wrong liquid.
What chemicals can I store in this tank?
It is intended for potable water and food-grade liquids and will hold lighter solutions in a pinch. Keep fuels, solvents, and flammables out, and check any chemical against a poly compatibility chart before storing it — most acids and bases are fine, but certain oxidizers attack polyethylene.
Does this tank come with a warranty?
Yes, under normal use it is backed by the manufacturer's warranty against material and workmanship defects. The coverage is for factory faults, not for storing an incompatible chemical, dropping the tank, or other misuse. File your receipt away in case a warranty claim ever comes up.
Can I install this tank underground?
No. Even at 40 gallons, this is an above-ground tank with a wall not built for soil pressure — burying it risks collapse and voids the warranty. For below-grade needs, use a small underground cistern designed for burial.
Buying Considerations
This is the simplest tank to site: confirm a small flat surface and a way to secure it, keep it near where the water is used to shorten the plumbing, and remember that its low weight makes it easy to relocate later if your needs grow.
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