Water

Stored drinking water is the most useful household supply you can have. After a hurricane, flood, or long outage, tap water may stop, lose pressure, or become unsafe. Do not count on filling a bathtub or reaching a store at the last minute.

How much to store

Ready.gov and the American Red Cross both use 1 gallon per person per day for drinking and sanitation. A typically active person may drink about three-quarters of a gallon; the rest of that gallon covers hygiene, cooking, and a margin for heat. Children, nursing parents, and people who are ill often need more. In very hot weather, Ready.gov notes that needs can double, which matters in Lowcountry summers when air conditioning is out.

For a family of four:

Add extra water for each pet; the 3- and 14-day calculator works out the pet water for you. Heat and activity raise needs. If someone in the house has a medical need that uses extra water, add that too.

Never ration drinking water on your own unless authorities tell you to. Drink what you need today and look for a safe source for tomorrow. Reduce how much you need by staying in the shade, limiting hard work in the heat, and avoiding alcohol and heavy caffeine.

How to store it

Best option: commercially bottled water, left in its original sealed containers, in a cool, dark place. Keep it off concrete if you can, and do not store it next to gasoline, pesticides, or household chemicals. Check dates and rotate.

If you fill your own containers: use food-grade water barrels or jugs. Ready.gov says to wash them with dish soap, then sanitize with 1 teaspoon of unscented household chlorine bleach in a quart of water, rinse, and fill with chlorinated tap water. That bleach mix is only for cleaning the empty container, not for drinking. Do not use empty milk jugs; the plastic degrades and is hard to clean. Dedicated food-grade containers are better for a 14-day supply.

Replace water you bottled yourself when the clocks change in March and November, which matches the roughly six-month interval Ready.gov recommends. Label containers with the date.

A water heater can hold many gallons of potentially usable water, but only if you know how to isolate it and drain it safely, and only after you have shut off power or gas to the heater so it cannot run dry. Learn that procedure now, from the heater manual or a plumber, not during a flood. Do not use water from a heating-system boiler or radiator; the CDC warns that this water can make you sick.

Water that cannot be made safe by boiling or disinfecting

The CDC is explicit: you cannot make water containing fuel, toxic chemicals, or radioactive materials safe by boiling or disinfecting it. If you know or suspect your water contains fuel or toxic chemicals, use bottled water or a different source of water, and contact your health department for specific advice.

Do not drink or cook with floodwater. Per CDC, boiling or disinfecting will not make water that may contain fuel, chemicals, or other toxic contaminants safe. Get water from another source: your stored supply, bottled water, or an official water distribution point.

Official wording, from CDC, How to Make Water Safe in an Emergency:

You cannot make water containing fuel, toxic chemicals, or radioactive materials safe by boiling or disinfecting it. If you know or suspect your water contains fuel or toxic chemicals: 1) Use bottled water or a different source of water 2) Contact your health department for specific advice.

The EPA likewise states that boiling or disinfection will not destroy other contaminants, such as heavy metals, salts, and most other chemicals. Those methods are for killing disease-causing microorganisms, not for chemical pollution.

If you need to treat water for germs

Use bottled or already-stored water first. If you have no safe stored water, and the water is not suspected of chemical or fuel contamination, you can boil or disinfect it to kill most disease-causing germs. Follow local health-department instructions, including any boil-water advisory.

The EPA says to use only water that has been properly disinfected for drinking, cooking, prepared drinks, washing dishes, and brushing teeth.

Boiling

Boiling is the most reliable household way to kill germs. EPA emergency disinfection guidance: if the water is cloudy, let it settle and filter it through a clean cloth, paper towel, or coffee filter. Bring the clear water to a rolling boil for at least one minute. At altitudes above 5,000 feet, boil for three minutes. Charleston is essentially at sea level, so one minute applies. Let the water cool naturally and store it in clean, covered containers. Pouring it between two clean containers, or adding a pinch of salt per quart, can improve the taste.

The CDC also recommends a 1-minute rolling boil (3 minutes above 6,500 feet). The two agencies use slightly different altitude cutoffs; both give a 1-minute boil at Lowcountry elevation.

Disinfection with household bleach (EPA table)

Use bleach only if you cannot boil. Use only regular, unscented liquid chlorine bleach that is suitable for disinfection, as indicated on the label. The label’s active ingredient is typically 6% or 8.25% sodium hypochlorite. Do not use scented, color-safe, “splash-less,” or bleach with added cleaners. Use bleach stored at room temperature for less than one year. If the water is cloudy, let it settle and filter it first.

The table below is the EPA’s current emergency disinfection table. Double the amount of bleach if the water is cloudy, colored, or very cold.

Bleach may contain 6% or 8.25% sodium hypochlorite. Source: EPA, Emergency Disinfection of Drinking Water.

Use a clean dropper. Stir, and let the water stand 30 minutes. It should have a slight chlorine odor. If it does not, repeat the same dose and wait another 15 minutes. If there is still no chlorine odor, do not drink it; find another source. If the chlorine taste is too strong, pour the water between clean containers and let it stand a few hours.

These doses are for making water microbiologically safer to drink. They are not the same as the stronger bleach mixes used to sanitize flood-soaked surfaces; those are on the sanitation page and must never be drunk.

For pool shock (calcium hypochlorite), safe storage of bleach and other household chemicals, and the combinations that must never be mixed, see Chemicals and water treatment safety.

Portable hiking filters can be a useful complement in a go-bag if you use them as the manufacturer directs and understand what they do and do not remove. They are not a reason to skip stored water, and they do not make fuel- or chemically contaminated water safe.

Using water carefully

• Drink known-safe stored water first.
• Keep a share for sanitation: handwashing, cleaning wounds, and a basic toilet setup if the sewer is out. See Sanitation and hygiene.
• If officials issue a boil-water advisory, follow it even if the tap looks clear. Advisories come from your water utility. Emergency and boil-water contacts for Charleston Water System, Berkeley County Water & Sanitation, Dorchester County Water & Sewer, Summerville CPW, Mount Pleasant Waterworks, and City of Goose Creek water customers are on the local resources page.
• After a flood, household pipes and filters may themselves be contaminated. Wait for the utility’s guidance before drinking from the tap again.

Sources & further reading

• CDC: How to Make Water Safe in an Emergency (fuel and toxic chemicals; boiling)
• EPA: Emergency Disinfection of Drinking Water (bleach table and boiling times)
• Ready.gov: Water (how much to store; container sanitizing and six-month rotation)
• American Red Cross: Survival Kit Supplies
• Charleston County Emergency Management: Emergency Supplies Kit
• Charleston Water System: Water Emergencies
• Berkeley County Water & Sanitation Contact
• Dorchester County Water & Sewer Service Requests
• Summerville CPW: Boil Water Advisory
• Mount Pleasant Waterworks Contact
• City of Goose Creek: Water Billing and Collection