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Weight · Water

How much does water weigh?

8.345 lb/gal · 1.00 kg/L · specific gravity 1.000.

Water weight at common tank volumes (8.345 lb/gal typical)
VolumePoundsKilograms
1 gal8 lb4 kg
5 gal42 lb19 kg
55 gal459 lb208 kg
100 gal835 lb379 kg
275 gal2,295 lb1,041 kg
330 gal2,754 lb1,249 kg
500 gal4,172 lb1,893 kg
1,000 gal8,345 lb3,785 kg
5,000 gal41,725 lb18,926 kg

Basis

Pure water at 60°F, NIST reference density. The cleanest number on this page — 1 kg per litre, 8.345 lb per US gallon. Liquid weight excludes the container — add tare weight for transport math. Matching tank charts: 55 gal tank · 275 gal tank · 330 gal tank · 500 gal tank · 1000 gal tank.

FAQ

How much does a gallon of water weigh?

8.345 lb/gal. That is 1.00 kg per litre (SG 1.000).

How much does a 55-gallon drum of water weigh?

About 459 lb of liquid, plus roughly 40–50 lb for a steel drum. A brim-full drum actually holds ~57.7 gal — see the drum chart.

Does temperature change this?

Yes — liquids expand when warm. Hydrocarbons move roughly 0.4% per 10°F; the figure here is the standard reference temperature value.