Capacity to Dimensions Reference

Approximate dimensions for vertical rotomolded polyethylene tanks. Exact dimensions vary by manufacturer model; check the spec sheet for the specific tank you're considering.

Weight Calculator

Empty-tank weights above are the polyethylene shell only. To calculate the loaded weight:

Loaded weight = empty weight + (capacity in gallons) × 8.34 lbs/gal × fluid specific gravity)

Water SG = 1.00. For other fluids see our ASTM SG decoded blog post which has an SG table for 13 common industrial fluids.

How to Size Your Tank — By Application

Potable Water / Utility Water

Residential whole-house water tanks typically target 1,000–1,500 gallons for a 3–4 bedroom home served by a well with variable flow. For continuous municipal supply, 500–1,000 gallons is often adequate. For off-grid cisterns, size to 2–4 weeks of average usage.

Commercial buildings: 1–2 gallons per employee per day, or 2–4 gallons per resident-day for assisted-living. Size for 1–2 days of demand plus fire-suppression reserve if applicable.

Septic Tanks (OSSF)

Septic tank sizing is state-regulated. See our State Regulation Guides for the specific bedroom-to-capacity table that applies in your state. General ranges:

• 1–3 bedroom home: 750–1,000 gallons (depends on state)
• 4 bedroom home: 1,000–1,250 gallons
• 5+ bedroom home: 1,500–2,000 gallons
• Commercial: design-flow based, commonly 1,500–5,000+ gallons

Always confirm with your local health department — state rules establish the minimum; counties often require stricter sizing in high-groundwater zones.

Chemical Storage

Chemical tank sizing usually targets 15–30 days of supply at peak draw rate. This balances:

• Delivery logistics (chemical trucks are typically 3,500–5,500 gallons; tank capacity should be 1.5–2x delivery-truck capacity)
• Shelf-life considerations (some chemicals degrade — see our Chemical Compatibility Database)
• Process continuity (larger tanks buffer delivery interruptions)

For redundant installations, size each of two tanks to full demand capacity plus a 10–20% swap-over buffer so service can continue while one tank is offline for inspection.

Fuel & Oil

Fuel tank sizing is dominated by regulatory capacity thresholds:

• <1,100 gallons: typically exempt from SPCC requirements at the federal level
• 1,100–10,000 gallons: SPCC plan required (40 CFR 112)
• Above 10,000 gallons: SPCC + typically double-wall construction required

Size for 30–60 days of consumption at peak-season rates. Fuel is typically delivered 3,500–8,800 gallons per truck.

Installation Space Planning

Doorway Access

The tank must physically fit through the doorway of the building where it will be installed. Standard residential doorways are 32" wide; commercial entrances often 36". For tanks wider than 32":

• Remove the door and casing temporarily (widens clearance by 2–4 inches)
• Tilt the tank on a dolly to pass through (requires 2–3 movers)
• Choose a horizontal-leg tank shape if vertical won't fit
• Order a "doorway" series tank (specifically designed narrow-profile)

Ceiling Clearance

Add 12–18 inches to the tank height for fill-line connection and manway access.

Setbacks from Structures

Fire-code minimums vary; typical values for residential:

• Propane/fuel tanks: 10 feet from building, 10 feet from property line
• Chemical tanks: varies widely by chemistry — consult your state/county rules
• Potable water tanks: typically just convenience-driven, no fire-code minimums

Delivery & Handling

Truck Access

For tanks 1,000 gallons and above, truck access is usually by flatbed. Confirm your delivery location can accommodate:

• 40-ton flatbed truck (for tanks above 2,500 gallons)
• Forklift offload (larger tanks are typically skidded and lifted off)
• Driveway grade — steep driveways may require special offload coordination
• Overhead clearance (power lines, tree limbs)

Lead Times

Typical manufacturer lead times:

• Common sizes (1,000, 1,500, 2,500 gal) in stock configurations: 2–4 weeks
• Specialty resins (sulfuric #880046, UV-stabilized #880059): 4–8 weeks
• Custom fittings or configurations: 6–12 weeks
• Seasonal peaks (spring fertilizer, pre-winter fuel): add 2–4 weeks

Freight Class

Polyethylene tanks ship LTL for smaller sizes (under 1,500 gallons) and truckload-dedicated for larger. Freight class is typically NMFC class 150 for empty tanks. Budget $800–$2,500 for delivery within 500 miles depending on tank size and access requirements.

Putting It All Together

The full tank-ordering checklist:

1. Fluid identified — chemistry, concentration, service temperature.
2. Capacity determined — 15–30 day supply at peak draw, adjusted for delivery schedule.
3. ASTM SG rating selected — see our ASTM SG Decoded guide. Match or exceed fluid SG.
4. Dimensions verified — will fit through doorway and under ceiling clearance.
5. MOC stack confirmed — resin, fittings, gaskets, bolts per our compatibility database.
6. State/county permit secured — for septic, chemical storage, or fuel.
7. Delivery scheduled — truck access confirmed; offload equipment ready.

We guide customers through every step of this checklist. Call (866) 418-1777 or email us with your application and we'll spec the complete package.