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Water units converter

Acre-feet, gallons, cubic feet, and flow rates, converted both ways.

Gallons
Cubic feet
Household-years
Applied depth over the acres

Exact conversions: 1 acre-foot = 43,560 cubic feet = 325,851 gallons (an acre-foot is one acre covered a foot deep). One cubic-foot-per-second sustained for a day is about 1.9835 acre-feet. Household-years use an average US household of about 300 gallons a day (~109,500 gallons a year), per EPA WaterSense — real household use varies widely. Flow figures assume the rate holds steady.

Common questions

How many gallons are in an acre-foot?

An acre-foot is 325,851 gallons — one acre of surface covered a foot deep. It is also 43,560 cubic feet.

How do you convert cfs to acre-feet?

One cubic foot per second sustained for a full day is about 1.9835 acre-feet. Multiply cfs by 1.9835 for acre-feet per day.

How many households does an acre-foot of water serve?

At an average of about 300 gallons a day, an acre-foot (325,851 gallons) covers roughly three household-years of indoor and outdoor use. Actual use varies a lot by region and season.