Where to find hidden water in your home in an emergency
The short answer
The CDC lists your water heater tank, ice cubes made with clean water, the toilet tank (not the bowl) and the liquid in canned fruit and vegetables as emergency drinking water. The water left in your pipes counts too. Never drink water from radiators, home heating boilers, waterbeds, pools or spas. If officials say your tap water may be unsafe, shut off your home's main water valve first, so the clean water inside stays clean.
What you can drink and what you can't
| Source | Drink it? | What to know |
|---|---|---|
| Water heater tank | Yes | Only the tank that feeds your taps and showers, not a home heating system tank. Steps below. |
| Water in your pipes | Yes | Shut the main valve first. Steps below. |
| Ice cubes | Yes | Only if they were made with water that wasn't contaminated. |
| Canned fruit and vegetables | Yes | The liquid in the can counts as water. |
| Toilet tank, not the bowl | Last resort | The CDC allows it if it's clear and has no toilet cleaner in it. Some local agencies say not to drink it, so we'd use it for washing and flushing, or make it safe first. |
| Pool or spa | No | Use it for washing and cleaning only. |
| Radiators and heating boilers | No | They're part of your heating system, not your drinking water. |
| Waterbed | No | FEMA says it may contain fungicides or chemicals from the vinyl. |
First, shut off the main valve
If officials say your tap water may be contaminated, the CDC says you may need to shut off your home's main water valve. That keeps dirty water out of your pipes and your water heater, so the water already inside stays usable. Find the valve now, while nothing is wrong, and make sure everyone at home knows where it is.
How to get water from your water heater
These steps follow Alameda County's emergency water guide, with safety notes from DC Water:
- Make sure the water heater and anything electrical near it are not under floodwater.
- Turn off the electricity or the gas to the water heater.
- Close the water intake valve on the cold water pipe that feeds the tank.
- Open a hot water faucet in your home to let air in.
- Open the drain valve at the bottom of the tank and collect the water in clean containers.
- Careful, it can be hot. Let the tank cool before you drain it, and keep children and pets away.
- Expect some sediment. Let the water settle, then pour off the clear water on top.
- Don't turn the power or gas back on while the tank is empty. Refill it first.
- How much is in there? The capacity is printed on the label on the tank.
How to get water from your pipes
- Shut off the main water valve.
- Open the faucet on the highest floor of your home to let air into the pipes.
- Collect the water from the lowest faucet in your home.
When in doubt, make it safe
If you're not sure a source is clean, the CDC's advice is to boil clear water at a rolling boil for 1 minute, or 3 minutes above 6,500 feet. If it's cloudy, filter it through a clean cloth, paper towel or coffee filter first, or let it settle and pour off the clear water. The CDC's page on making water safe also explains how to disinfect it with bleach.
Hidden water is a backup, not a plan
The water already in your home helps, but you can't count on it. Pipes may be contaminated and a water heater may be damaged. Store water you know is safe first. The water storage calculator tells you how much for your household, and our guide to how long stored water lasts tells you when to replace it.