| 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 Tank Depot, Amazon, and Tractor Supply. 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 |
|---|---|---|---|
| Tank Depot | $189–$229 | Freight or local pickup | Best selection; many sizes, styles, and fittings options |
| 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 selection vs. Tank Depot |
| 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.