300 Gallon Plastic Water Storage Tank - Black (35" x 89"): Complete Buyer's Guide
300 Gallon Plastic Water Storage Tank - Black (35" x 89") 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
An 89-inch-tall tank on a 35-inch base is built to hold 300 gallons in a vertical slot, and that tall proportion is the first thing to respect when you install it. Nearly seven and a half feet of loaded poly puts its weight down through a compact footprint, so a flat base and a guard against tipping outrank everything else — a column this tall is far less tolerant of a leaning pad than a squat tank.
Site Preparation
Pour or build a level four-inch pad, or compact a stone bed, a few inches wider than the 35-inch base all around, and fuss over flatness more than you would on a wide tank. A slim 89-inch shell that sits even a little off-level walks its load to one side and overstresses the lower wall. If the tank stands where carts, vehicles, or doors could reach it, strap the upper body to a wall or post.
Placement and Connections
Run the discharge off the lowest fitting and keep the plumbing tight to the tank. Use a flexible connector on the first stretch instead of rigid pipe, because a tall black column shifts most at its top as it fills and warms in the sun, and a hard line drives that movement into the bulkhead. Hand-tighten and add a quarter turn; a pipe wrench on poly is how the threads split.
Venting
Even 300 gallons must breathe, and on a tall tank the pressure swing concentrates near the lid. Keep the lid vent open and screened so air flows in as you draw down — a blocked vent can suck the upper wall inward on a slim shell faster than you would expect — and out again as you refill, with the screen keeping pests and grit at bay.
Maintenance and Long-Term Care
Three hundred gallons of potable water in a tall black tank needs only a light, regular touch, and the dark wall already keeps light-fed algae from gaining a foothold. The routine here is mostly about keeping the water fresh and catching any lean before it becomes a stress problem.
Quarterly Inspection Checklist
- Plumb check: Sight up the 89-inch column for any bow or lean; on a tall tank a small base tilt magnifies toward the top.
- Outlet feel: Run a hand over the bottom fitting for dampness and re-snug by hand if it has loosened.
- Base level: Confirm the small footprint pad has not settled on one side after rain or frost.
- Vent and lid: Make sure the screened vent is open and the lid seats so contaminants stay out of the water.
Cleaning
Drain the 300 gallons through the bottom once a year, rinse, and sanitize on the refill with roughly a quarter cup of unscented bleach per fifteen gallons, two hours of contact, then flush the chlorine out. The yearly reset clears settled sediment and resets the freshness clock on a reserve that turns over slowly.
UV and Weather Protection
Black resin gives this column the toughest UV defense of any color, but the stabilizer still depletes over years of direct sun. Check the bright side each year for chalking; if the tank lives in harsh light, even a partial shade or a north-side placement adds meaningful service life.
Alternatives and Comparisons
This tall 35-by-89 black tank holds 300 gallons in the smallest possible floor area, while a shorter, wider 300-gallon version trades that for a more stable stance. Drop a size to ease the pad and freight, or step up where the reserve needs to be bigger. The options below let you balance height against footprint.
Other -Gallon Options
Frequently Asked Questions
How long will the 300 Gallon Plastic Water Storage Tank - Black (35" x 89") last?
On a flat base, within rating, with the light annual sanitize, this 300-gallon black column runs well past fifteen years. The one-piece wall has no seam to part and black is the most UV-durable color offered; a tilted base or stale water is what shortens a tall tank's life, not the polyethylene.
What chemicals can I store in this tank?
It is made for potable water and food-grade liquids and will hold lighter solutions within reason. Keep flammables, fuels, and solvents out, and check any chemical on a poly compatibility chart first — most acids and bases are fine but a few oxidizers and hydrocarbons attack the resin.
Does this tank come with a warranty?
Yes — Norwesco backs it against material and workmanship defects under normal use, covering factory faults but not overfilling, a leaning install, chemical attack, or impact. Keep proof of purchase and an install photo on hand should you need to claim.
Can I install this tank underground?
No. The flat vertical wall is engineered for above-ground service and cannot take soil load; burying it risks collapse and voids the warranty. Choose a ribbed underground cistern for below-grade storage.
Buying Considerations
Check that an 89-inch tank clears your ceiling or eave where it will stand, that the narrow base can sit dead-level since tall tanks punish slope, and that you can brace or strap it if it lives in a spot where it might be struck.
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