A daily water intake of 3.7 L (approx. 1 gallon) for adult men and 2.7 L (approx. 3/4 gallon) for adult women meets the needs of the vast majority of persons. However, strenuous physical exercise and heat stress can greatly increase daily water needs. (Ref. 1.). Based on this data it is recommended to store 1 gallon per person / per day.
| Storage | 3 Day | 3 week | 3 month |
| gallons (per person) | 3 | 21 | 90 |
| gallons (per family 4) | 12 | 84 | 270 |
Reference 1. Sawka MN, Cheuvront SN, Carter R 3rd. Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA 01760-5007, USA. michael.sawka@us.army.mil. Nutr Rev. 2005 Jun;63(6 Pt 2):S30-9.