Your water calculator
Calculation: 1 gallon per person per day for drinking and basic hygiene (Ready.gov), plus about 1 quart per pet per day. Hot weather, nursing mothers and illness can double the need.
Why this matters more than most people think
Tap water depends on electricity. Treatment plants and pumps need power, so a big storm can cut your water and your lights at the same time. During the February 2021 Texas freeze, more than 12 million people were told to boil their water at the peak, according to state figures reported by NPR.
Water is also the heaviest and bulkiest thing to store. Two weeks for your household is 46 gallons, or about 384 pounds.
3 ways to cover the gap
| Option | Good for | Watch out for |
|---|---|---|
| Store Start here | Short emergencies. Cheap and simple. | Takes space. Rotate every 6–12 months. |
| Filter | When you have a water source (rain barrel, creek, pool) that isn't safe to drink. | You still need a source of water. |
| Make it from air Long outages | An extra source of water at home. Pulls moisture from the air, like a dehumidifier. | Needs electricity (or solar) and works best in humid climates. Store-bought units often cost hundreds to thousands of dollars. |
Build your own water-from-air unit at home
If you'd rather not spend hundreds or thousands on a ready-made machine, Water Freedom System is a step-by-step guide to building a small atmospheric water generator yourself, with parts from a hardware store or Amazon. Its author explains how it works in a free video.
- It's a guide, not a machine. You buy the parts separately and build it.
- Output depends on humidity and temperature. Treat it as a backup source, not a replacement for your water line.
- The unit needs power. Pair it with solar or a battery if you want it to work in an outage.
- The video is long and the marketing is enthusiastic. Check the current price and refund terms on the seller's page.
Opens the seller's website. We may earn a commission if you buy, at no extra cost to you.
Do this today, whatever you decide
- Buy or fill enough water for 3 days (use your number above).
- Store it in a cool, dark place, away from chemicals.
- Write the date on each container and set a reminder to rotate it.
- Learn how to shut off your home's water main, in case pipes burst.
- Keep unscented household bleach: CDC guidance explains how to use it to disinfect water in an emergency.
Sources: Ready.gov, Build a Kit; CDC, Water in emergencies; NPR, Feb 22, 2021. This site is independent and is not affiliated with Ready.gov, CDC or any government agency.