| Capacity | 100 US gallons / 378.5 liters / 13.4 cubic feet |
| Weight Empty | 25–40 lbs (poly) · varies by material and brand |
| Weight Full | ~835 lbs (water only) · ~860–875 lbs total loaded |
| Typical Dimensions (Vertical) | 24" diameter × 46" tall (Norwesco standard) |
| Typical Price Range | $120–$350 (poly) · $400–$900 (fiberglass) |
| Common Materials | Polyethylene (HDPE), Fiberglass, Galvanized steel |
| Common Uses | Home emergency backup, mobile detailing, RV top-up, small farm, pressure washing buffer |
| Potable Water Rated? | Yes — when specifically labeled for potable use (HDPE tanks) |
Who Needs a 100 Gallon Water Tank?
The 100-gallon water tank is the most popular residential size for good reason — it's large enough to matter in an emergency or work scenario, but small enough to fit in a truck bed, garage corner, or RV storage bay. It sits in a practical middle ground that most smaller tanks can't fill and most larger tanks can't reach without a dedicated installation.
- Emergency water storage: 100 gallons provides about a 50-day supply for one person at the FEMA-recommended 1 gallon/day survival minimum, or about 8 days for a family of four at a more realistic 3 gallons/person/day.
- Mobile auto detailing: The most common tank size used in mobile detail rigs. A 100-gallon tank on a trailer or truck bed supports a full day of washing without a water hookup.
- Pressure washing buffer tanks: Eliminates cavitation issues when operating off a low-flow residential hose bib. Keeps the pump fed even when supply flow drops.
- RV and off-grid water supply: Fits in many truck beds for top-up use at campsites, or mounts in utility trailers alongside an RV.
- Small livestock operations: Sufficient for watering a small number of cattle, goats, or horses when paired with a float valve.
Dimensions by Style
100-gallon poly tanks come in four main configurations. Vertical round tanks are the most common. Horizontal tanks are useful for vehicle or trailer mounting where height is limited.
| Style | Diameter / Width | Height / Length | Footprint | Typical Brand |
|---|---|---|---|---|
| Vertical Round | 24" | 46" | ~3.1 sq ft | Norwesco, Snyder |
| Horizontal Round | 24" dia | 57" long | ~8 sq ft | Norwesco, Chem-Tainer |
| Leg Tank (Vertical) | 24" | 46" + legs | ~3.1 sq ft | Norwesco |
| Slimline / Low Profile | 18"–22" wide | Varies | Narrower footprint | Chem-Tainer, DenHartog |
| Dimensions are approximate. Always confirm with the manufacturer spec sheet before ordering. | ||||
Material Options
Polyethylene (HDPE) — Best for Most Uses
High-density polyethylene is the go-to material for 100-gallon water tanks. It's rotationally molded (seamless), UV-stabilized, and FDA-approved for potable water storage when labeled as such. Norwesco and Snyder are the two dominant domestic manufacturers — both produce high-quality tanks from virgin (not recycled) resin.
- Lightweight (25–40 lbs empty)
- Seamless — no welds to fail
- FDA-approved for potable water
- No rust, no corrosion
- Most affordable option
- Widely available
- Degrades with prolonged direct UV exposure (use UV-stabilized resin)
- Not suitable for fuels, chemicals, or solvents
- Can absorb odors if improperly cleaned
- Less impact-resistant than steel
Fiberglass
Fiberglass tanks at 100 gallons are less common but useful when extreme chemical resistance or custom shapes are needed. They're more expensive ($400–$900) and heavier than poly, but won't react with the stored liquid. Most common in agricultural chemical storage and marine applications. Not the right choice for simple potable water storage — poly is better value.
Galvanized / Corrugated Steel
Steel tanks at 100 gallons are rare — steel becomes cost-competitive at larger sizes (1,000+ gallons). At this capacity, a corrugated steel tank offers durability and impact resistance but adds significant weight and requires rust prevention treatment on interior surfaces. Stick with poly unless you have a specific reason for steel.
Top 100 Gallon Water Tank Picks (2025)
We evaluated the most widely purchased 100-gallon tanks across Amazon, Tractor Supply, and farm supply networks. Selection criteria: build quality, UV resistance, fitting options, buyer reviews, and value.
Accessories You'll Need
A tank alone isn't a complete system. For most 100-gallon setups you'll also need:
- Transfer Pump: A 12V DC transfer pump (like the Shurflo 2088 or Flojet) is the standard for mobile use. For stationary setups, a small 110V centrifugal pump works well. Expect to spend $40–$150.
- Hose & Fittings: ¾" or 1" hose barb fittings are standard. Most 100-gallon tanks ship with a single threaded outlet; you'll need a bulkhead fitting for inlet plumbing. Budget $10–$30.
- Tank Pad or Stand: A 2"–3" thick rubber or poly pad helps distribute weight and prevents abrasion. Not required but recommended on rough surfaces.
- Lid / Vented Cap: Most tanks include a lid, but a vented cap prevents vacuum build-up during pumping. Essential for enclosed systems.
- Straps or Tie-Downs: For vehicle transport, use ratchet straps rated for at least 1,000 lbs. Never transport a full 100-gallon tank unsecured (835 lbs of moving water can be catastrophic).
Where to Buy a 100 Gallon Water Tank
| Retailer | Typical Price | Shipping | Notes |
|---|---|---|---|
| Amazon | $165–$280 | Free Prime shipping on many | Easiest returns; check seller carefully for non-Fulfilled items |
| Tractor Supply Co. | $179–$249 | In-store pickup available | Good for standard sizes; limited to smaller tanks in most stores |
| Home Depot | $199–$299 | Delivery or store pickup | Limited selection; sometimes has Norwesco in-store |
| Local Farm Supply | Varies | In-store pickup | Often carry Norwesco; no shipping; may negotiate on price |
Installation Considerations
At 835–875 lbs when full, a 100-gallon tank is heavy but manageable for most residential surfaces. Here's what to account for:
- Ground prep: Flat, firm, level surface. A 2"–3" rubber or poly pad is recommended. On soil, compact gravel or a concrete pad eliminates settling over time.
- Indoors: Concrete basement floors or garage slabs handle the weight easily. Wood subfloors require assessment — 875 lbs concentrated in a 24" circle (about 2.9 sq ft) creates approximately 300 psi of load. Consult a contractor if uncertain.
- Access for filling: Standard garden hose inlet or a top-fill opening. Make sure you can get a hose to the fill port.
- Overflow planning: Install an overflow fitting at the maximum fill line. A full tank with no overflow will push through the lid under fill pressure.
- Regulations: 100-gallon tanks rarely require permits. However, if connected to a potable water system or in commercial use, check local plumbing codes.
Frequently Asked Questions
A standard vertical round 100-gallon poly tank (Norwesco) measures approximately 24 inches in diameter and 46 inches tall. Horizontal versions run approximately 24" diameter × 57" long. Slimline tanks vary. Always confirm the exact spec sheet from the manufacturer before ordering, as dimensions vary by brand and year.
Water weighs 8.345 pounds per gallon. A full 100-gallon tank contains approximately 834.5 pounds of water. Add the tank's empty weight (typically 25–40 lbs for poly) for a total loaded weight of roughly 860–875 lbs. Plan your floor and transport accordingly.
Yes, provided the tank is specifically rated for potable water. Look for tanks labeled "FDA-approved," "NSF/ANSI 61," or "safe for drinking water." Both Norwesco and Snyder sell potable-rated 100-gallon tanks. Never use a tank that was previously used for chemicals, even if cleaned — residual contamination is a real risk.
Yes, for most full-size pickups. A standard vertical 100-gallon tank (24"Ø × 46"H) fits easily in a 6.5' or 8' bed. Crew cab short beds (5.5') are tight but manageable. For regular transport, a horizontal "transport tank" (24"Ø × 57"L) sits lower and is more stable — it's the better choice for truck beds and trailers.
Standard poly 100-gallon vertical tanks cost $120–$350 depending on brand, retailer, and configuration. Norwesco and Snyder are the most reputable brands and typically run $165–$230. Horizontal and specialty tanks run slightly higher. Fiberglass alternatives start around $400. Skip any unbranded tanks under $100 — quality control is typically poor.
A quality Norwesco or Snyder tank carries a 3-year warranty but realistically lasts 20–30 years under normal conditions. Key factors: keep it out of direct prolonged UV exposure (black tanks are UV-stabilized but even they benefit from shade), don't store it empty for long periods in freezing temperatures, and use the proper fittings (brass or poly — avoid iron). Inspect the outlet fitting annually for cracks.
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Water and wastewater treatment professional with 18+ years of hands-on industry experience. Holds a Grade IV Wastewater Certification and has operated systems ranging from frac tank flow equalization setups to refinery DAF units and metals pretreatment facilities. He founded TankAuthority to bring real operator knowledge to water storage decisions.