From Daily Use to Emergency Preparedness
By Larry Betz | Prepared Not Paranoid https://www.preparednotparanoid.com/
You can go 3 weeks without food, but only about three days without water.
When a main breaks, a storm hits, or a boil water notice goes out, most families find out the hard way that they have a case of bottled water and no plan. This post fixes that: how much your family needs, how to stretch it, and how to make questionable water safe to drink.
Calculating Water Needs and Requirements
To make sure your family has enough water in an emergency, start by calculating your daily water needs. Plan on 1 gallon per person per day as the minimum (for drinking and basic hygiene), and up to 2 gallons per person per day if you live in a hot climate like Arizona, are physically active, or want water for cooking and cleaning. The CDC says to store more for pregnant or nursing women, people who are sick, and pets.
Be sure to include your pets. A common rule of thumb is about 1 ounce of water per pound of body weight per day for dogs and cats, so a 50-pound dog needs about 50 ounces (roughly 3/8 of a gallon) a day. Next, multiply your total daily water needs by the number of days you want to prepare for. FEMA and the CDC say a minimum of 3 days, and a 2-week supply if possible. I recommend 14 days as your minimum.
Example: A family of four plus one 50-pound dog, at 1 gallon per person:
At 2 gallons per person, that same family needs about 118 gallons.
Beyond drinking water, consider additional needs for hygiene and sanitation, such as cooking, brushing teeth, and cleaning utensils. To help conserve water, keeping items like Clorox wipes, shower wipes, and tub o' towels in storage can reduce unnecessary water use. Planning for both drinking and hygiene water needs ensures your household remains safe, healthy, and prepared for an extended emergency.
Signs of Dehydration
Staying properly hydrated is essential not only for peak physical performance but also for daily function, cognitive clarity, and overall health. Dehydration can creep up subtly, especially in hot climates or during physical activity, and recognizing the early signs can prevent more serious complications. Common symptoms of mild to moderate dehydration include thirst, dry mouth, headache, fatigue, dizziness, and decreased urine output. As dehydration worsens, signs can progress to rapid heartbeat, confusion, irritability, and dark-colored urine.
Watch the most vulnerable: Infants, young children, and older adults dehydrate faster. Older adults often don't feel thirsty even when they need water, so don't wait for them to ask.
Call 911 or get emergency care for confusion, fainting, no urination for 8 hours or more, a rapid heartbeat, or a baby with a dry diaper for several hours, sunken eyes, or no tears when crying.
Hydration Goal: Aim for Pale Yellow
A simple and effective way to monitor your hydration is to pay attention to your urine color and frequency. Ideally, you should be urinating several times a day, with urine that is pale yellow, about the color of lemonade. Dark yellow or amber urine is often a sign your body needs more water. Completely clear urine all day long can mean you're drinking more than you need. Consistent, pale yellow urination throughout the day tells you your body is well hydrated and working efficiently.
Why Electrolytes Help You Absorb Water More Effectively
Drinking plain water is important, but adding electrolytes, especially sodium, potassium, and magnesium, can improve how efficiently your body absorbs and uses that water. Electrolytes help maintain fluid balance, support nerve and muscle function, and help your cells hold onto water. When you sweat, exercise, or spend time in hot environments, you lose not just water but also these essential minerals. Replenishing them with a high-quality electrolyte mix like LMNT can help your body hydrate faster and more effectively than water alone. This is especially valuable in preparedness scenarios, during intense physical activity, or if you're showing signs of dehydration. Salt (sodium) in particular helps your body hold onto water rather than just flushing it out, which is why electrolytes can make such a difference.
A word of caution: LMNT and similar mixes are high in sodium (about 1,000 mg per stick). If you have high blood pressure, heart disease, or kidney disease, or take medication for any of these, talk to your doctor about which electrolyte option is right for you.
No electrolyte mix? Make your own. The World Health Organization's simple oral rehydration recipe has saved millions of lives:
1 liter (about 1 quart) of clean water
6 level teaspoons of sugar
1/2 level teaspoon of salt
Stir until dissolved. Measure carefully, because too much salt can make dehydration worse. For an infant or young child who is sick, call your pediatrician and use a store-bought pediatric solution if you have one.
Hidden Water Sources Already in Your Home
If the water stops before you've stored enough, you have more water in your house than you think. Ready.gov lists these safe sources:
Your water heater: A typical tank holds 40 to 50 gallons. Turn off the power or gas first, then drain from the valve at the bottom. Expect some sediment; let it settle.
Your toilet tank (the tank, NOT the bowl): Safe to use after you treat it, as long as you don't use chemical tank cleaners.
Ice cubes in your freezer.
Liquid from canned fruits and vegetables.
Water in your pipes: Open the highest faucet in the house to let air in, then collect water from the lowest faucet.
Do NOT drink: water from waterbeds, swimming pools, hot tubs, or radiators. Pool and hot tub water can be used for flushing toilets and cleaning, not drinking.
Protect what's in your pipes: If you hear reports of broken water lines or sewage problems, shut off the main water valve to your house so contaminated water doesn't flow in. Know where that valve is today, before you need it.
Clean Water Options
Various filtration and purification methods work well, and each one does a different job.
Here's how the main methods compare.
Nothing Fancy Needed: Boiling Water Works
Boiling water remains the simplest and most reliable way to make water safe to drink. The CDC calls boiling the surest method to kill disease-causing germs, including viruses, bacteria, and parasites like Giardia and Cryptosporidium. All you need is a heat source. To improve the flat taste of boiled water, pour it from one container to another, let it sit for a few hours, or add a pinch of salt per quart or liter.
What boiling does NOT do: It won't remove chemicals, heavy metals, nitrates, or fuel. If your water may be contaminated with chemicals, boiling can make it worse by concentrating them. Use a different water source.
Steps for Boiling Water
Step 1: Clear the water. If the water is cloudy, filter it through a clean cloth, paper towel, or coffee filter, or let it settle and carefully pour off the clear water.
Step 2: Boil. Bring the clear water to a rolling boil for at least 1 minute. Boil for 3 minutes at elevations above 6,500 feet (that includes Flagstaff).
Step 3: Cool. Let the boiled water cool before drinking.
Step 4: Store. Store it in clean, sanitized containers with tight-fitting covers.
Using Bleach to Disinfect Water in an Emergency
If boiling isn't an option, unscented household bleach can be used to disinfect water during an emergency. A few drops kill most bacteria and viruses, making the water safer to drink. Bleach is less effective against tougher parasites like Cryptosporidium and Giardia, which is why boiling is the better choice when you can. Bleach will not remove harmful chemicals, heavy metals, or radioactive contaminants.
Always look for the cleanest water source first.
Pay attention to the bleach concentration. In the United States, unscented household liquid chlorine bleach typically contains 5% to 9% sodium hypochlorite, but concentrations vary in other countries.
Use plain, unscented bleach only. Never use scented, color-safe, or "splash-less" bleach, or bleach with added cleaners.
Steps for Disinfecting Water with Bleach
Step 1: Clear the water. If the water is cloudy, filter it through a clean cloth, paper towel, or coffee filter, or let it settle before drawing off the clear water.
Step 2: Check the label. Follow the directions on the bleach label if it has them. If not, find the sodium hypochlorite percentage under "active ingredient."
Step 3: Measure. Use the correct amount of bleach for the concentration and water volume (see the tables below). Use a clean dropper.
Step 4: Stir and wait. Stir well and let it stand for at least 30 minutes before drinking.
Step 5: Smell test. The water should have a slight chlorine smell. If it doesn't, repeat the dose and wait another 15 minutes.
Step 6: Store. Store the disinfected water in clean, sanitized containers with tight covers.
If the water is cloudy, murky, colored, or very cold, double the amount of bleach listed below.
For 5% to 9% Sodium Hypochlorite (Standard Household Bleach)
Source: CDC, Making Water Safe in an Emergency.
Bleach doesn't last forever. It loses strength over time, faster in heat. Date your bottle and replace it about once a year so it works when you need it.
By following these steps, you can safely disinfect water in emergency situations and have a reliable drinking supply when other methods aren't available.
Water Purification Tablets
Water purification tablets are a convenient and effective way to disinfect water. They kill harmful microorganisms such as bacteria and viruses. These lightweight, compact tablets are especially useful when clean water is limited, such as camping, hiking, international travel, or an emergency. They're a great addition to every go-bag. Typically, a single tablet is added to a specified amount of water and left to work for a set time, usually around 30 minutes.
Know which kind you have:
Source: CDC.
For those seeking a reliable option in larger quantities, Aquatabs 397mg Water Purification Tablets (100 Pack) are a great value. Each tablet treats up to 5 gallons (20 liters) of water. Aquatabs are EPA-registered and have been trusted worldwide for over 30 years. Their ease of use and long shelf life make them a practical choice for personal and family kits. I also keep a pack of chlorine dioxide tablets in the go-bag for questionable water sources, since they're the only tablet the CDC says can handle Cryptosporidium. Always follow the directions on the package.
Filter, Then Disinfect
Here's the rule I follow for emergency water from an unknown source (a stream, a lake, rain barrel, or anything after a flood):
Step 1: Filter it to remove dirt, parasites, and many chemicals. The CDC recommends a filter with an absolute pore size of 1 micron or smaller to catch Giardia and Cryptosporidium.
Step 2: Disinfect it by boiling, bleach, or tablets to kill viruses and bacteria a filter may miss.
Most filters don't remove viruses, so doing both steps is the safest approach. Part 3 covers the best filters for home and emergency use.
What to Do During a Boil Water Advisory
When your city issues a boil water advisory, use boiled or bottled water for:
Drinking
Brushing teeth
Making ice
Mixing baby formula
Washing fruits and vegetables
Cooking
You can usually still shower and bathe; just don't swallow the water, and sponge-bathe babies and young children. Throw out ice made before the advisory. Follow your local health department's instructions, and don't stop until they say the advisory is lifted.
Ask Yourself
Do I have at least 14 days of water stored for every person and pet in my home?
Do I have unscented bleach that's less than a year old, and a dropper to measure it?
Do I know the signs of dehydration in my kids and my parents?
If the water stopped tonight, would I know where my water heater valve and main shutoff are?
Remember
Store it, know how to make it safe, and watch the most vulnerable. One gallon per person per day is the minimum, boiling is the surest way to kill germs, and pale yellow is the goal.
Get Started Today
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Go Deeper
The Prepared Not Paranoid Family Nutrition Guide. This post gives you the water math and the emergency methods. The guide adds the full hydration and electrolyte chapter, the 30-Day Food and Water Calculator, the Hydration Color Chart, and the Emergency Water Purification Card, with the bleach tables, boiling times, and tablet doses on one page for your kitchen and go-bag. [Get it here: LINK]
Tools I recommend: The LMNT electrolytes, Aquatabs, chlorine dioxide tablets, and water storage I recommend are in my Amazon store. https://amzn.to/4yM747h
Related reading:
Safe Drinking Water, Part 1: What's Really in Your Water https://www.preparednotparanoid.com/pnp-library/water-intro-3j5am
Safe Drinking Water, Part 3: Filters and Storage https://www.preparednotparanoid.com/pnp-library/water-storage
Nutrition Basics, Part 17: Your Family Food PACE Plan
References
Centers for Disease Control and Prevention. Making Water Safe in an Emergency.
Centers for Disease Control and Prevention. Creating and Storing an Emergency Water Supply.
Centers for Disease Control and Prevention. Water Disinfection for Travelers (CDC Yellow Book).
Ready.gov. Water: emergency water supply and hidden water sources.
FEMA. Food and Water in an Emergency.
World Health Organization. Oral rehydration salts: production of the new ORS; home-made solution guidance.
Centers for Disease Control and Prevention. Boil Water Advisories.
Disclaimer
This article is for general informational and educational purposes only. It is not medical advice. If you have high blood pressure, heart disease, or kidney disease, talk with your doctor before using high-sodium electrolyte mixes. For a sick infant or young child, call your pediatrician. Affiliate disclosure: I've linked to products from my Amazon store that I personally recommend. As an Amazon Associate, I earn from qualifying purchases, at no extra cost to you. Thank you for supporting my work.
If someone is confused, faints, hasn't urinated in 8 hours, or a baby shows signs of severe dehydration, call 911.
Awareness gives you time. Time gives you options.
The prepared protector is someone who's decided that loving someone means being ready for them, not just hoping things go fine.
Prepared Not Paranoid. Protecting the Most Vulnerable Among Us.
