Water Storage Tanks for Emergency Preparedness: Sizing and Safety

For emergency preparedness, choose a food-grade water storage tank sized to at least a few days of household needs, placed where it will not freeze or sit in strong sunlight. Government preparedness guidance commonly cites about one gallon per person per day for drinking and sanitation, with extra for pets and hygiene.

Work Out How Much Water You Need

Start with the household. Multiply the number of people by at least one gallon a day, then add water for pets, cooking and basic hygiene. Official guidance often suggests storing at least a three-day supply, and many households aim for two weeks if they have space. A family of four planning for a two-week outage would want something in the range of fifty-plus gallons for drinking alone, more if you include washing. Think about your local risks: hurricanes, winter storms and wildfire smoke each create different needs, and well owners lose water when pumps lose power.

Types of Storage Containers

Materials and Food-Grade Standards

Only store drinking water in containers labeled food-grade or made for potable water. Look for materials such as high-density polyethylene and for markings that indicate the container is intended for drinking water. Avoid reusing containers that previously held chemicals, and be cautious with milk jugs, which are hard to clean and may break down. Opaque, dark-colored containers reduce light, which discourages algae growth. Check for a tight lid, a spigot or a bung that seals well, and a base that handles the weight. A common starting point is a 55-gallon food-grade water barrel, though it weighs several hundred pounds when full.

Consider rotation and access as part of the plan. A tank no one can reach in an emergency is no help, so keep it where you can get at the spigot with a container underneath. Households with older adults or children should avoid very heavy containers that are difficult to move. Splitting storage between several smaller containers in different parts of the home also reduces the risk of losing everything to a single leak or a failed seal.

Placement, Temperature and Stability

Water weighs about eight pounds per gallon, so a full barrel requires a solid, level floor. Keep it out of direct sunlight, away from gasoline, pesticides and other chemicals whose vapors can pass through plastic, and protect it from freezing. If your area gets cold, leave some headspace to allow for expansion, or store indoors. A concrete garage floor or a ground-level closet is usually safer than an upper floor. Place a drip tray or a drain nearby, and consider a sturdy stand for tanks with spigots.

• Keep containers off bare concrete if the manufacturer advises a barrier.
• Label with fill date and the treatment used.
• Avoid stacking beyond the maker’s guidance.
• Use secondary containment in earthquake-prone areas.

Treating and Rotating Stored Water

Tap water from a municipal supply is already treated, but storage may need additional steps. Guidance from agencies such as the CDC and Ready.gov mentions using household bleach in specific small amounts or commercial water preserver products, and replacing stored water on a regular schedule. Follow current official instructions for dosing, as it depends on the bleach concentration. If your water comes from a private well or an untested source, test it before storing. Have a backup way to purify water, such as filters or purification tablets. A gravity water filter helps turn lake, rain or tank water into something safer to drink, but follow the product’s guidelines and consider boiling when advised.

Accessories and Maintenance

A pump or spigot makes a large tank usable, since tipping a full barrel is not practical. A hand siphon pump works for barrels and totes. Keep a few spare gaskets, hoses and cleaning supplies, and sanitize containers before filling. Check seals periodically for leaks, bulges or cloudiness, and rotate on a schedule that matches the manufacturer’s or agency’s recommendations. A barrel pump or siphon can save time. Keep a written checklist, and include a few smaller jugs that are easy to carry if you need to evacuate.

Remember that stored water is only one layer of preparedness. Note the location of your main water shutoff, learn whether your water heater tank can be used as an emergency source, and keep a list of local resources such as distribution points that open during disasters. Check local rules before installing large outdoor tanks or rain catchment systems, since regulations vary by state and municipality, and ask your utility about safe handling if your supply has been contaminated.

Common Questions

How long can stored water last?

It depends on container, treatment and conditions. Many agencies suggest replacing stored water periodically, so follow current guidance.

Is rainwater safe to drink?

Not without treatment. Collected rainwater can carry contaminants, so filter and disinfect it using approved methods before drinking.

Where should I store it if I live in an apartment?

Use stackable containers in closets or under beds, and respect weight limits. Check lease rules and floor loads before storing large volumes.