Water Storage Tank Size Calculator
Calculate the cistern or water storage tank size needed for your homestead based on daily water use, backup days, and fire safety requirements.
Why Store Water? Homesteads with slow-recovery wells, seasonal springs, or rainwater systems need a buffer tank. A cistern lets a 2 GPM well supply a family that needs 10 GPM peak, because the tank fills slowly and empties quickly when needed.
Sizing Rules of Thumb Daily household use: 50-100 gallons per person per day for typical US use. Emergency/off-grid conservative use: 15-30 gallons per person. Add livestock, irrigation, and fire suppression requirements.
Fire Storage Rural properties often need on-site water for fire department tanker access. A common requirement is 2,500-5,000 gallons minimum. Check local rural fire code.
Tank Materials Polyethylene (poly) tanks: affordable, widely available, 500-10,000+ gallons. Concrete cisterns: long-lasting, can be buried. Corrugated steel with liner: large capacity at lower cost. Underground tanks avoid freezing but cost more to install.