
You’ve probably watched kids play in the water. They freaking love it. It’s amazing how universally children will respond to an opportunity for water play. Odds are, if you take a kid at any age from any society at any point in human history, plop them in a kiddie pool, they’re going to have a good time. I don’t have any science behind this, but I suspect that there is an evolutionary pressure working here:
Societies located near ample water have a better chance of surviving. If I have enough water to let me kids play in it, then I probably have enough to endure a dry spell. Not to mention enough to wash my body in. Close to water could also mean close to game and fish. Close to water means you can irrigate crops.
Anyway, water is important. We need it. Fast-forward to modern days and our need for water has only increased. Modern humans have the same biological needs for water as ancient humans, and we’ve grown accustomed to some creature comforts since we crawled out of the mud. Comforts like flushing toilets. Clean clothes. Hygiene.
Let’s prepare to stay hydrated in an emergency.
How Much Water Should I Have For an Emergency?
We’re looking for a minimum of a gallon per day per person. 2 Gallons per person is better. One gallon is biology / survival. Two gallons is hygiene, cooking, and convenience. Most emergencies will last three days or less, so that’s where we start for basic preparation. Having said that, I STRONGLY RECOMMEND you get closer to a week of drinking water. For guidance, 3 gallons per person is the minimum, and covers drinking for 3 days.. 14 gallons per person gets you fully prepared for a week with a gallon for drinking and another gallon for cleaning each day for a week.
Here’s simple math:
[Number of People] X 3 = Minimum # of Gallons you Need. (One gallon per person per day for 3 days).
[Number of People] X 3 X 2 = Target # of Gallons. (Two gallon per person per day for 3 days).
If you are alone, you need 3-6 gallons.
For my family of four, I’m looking for 12-24 gallons.
Here is a simple chart showing how much water you need for a 3-day emergency:
Number of People in Home | Gallons of Water – Minimum | Gallons of Water – Recommended |
1 | 3 | 14 |
2 | 6 | 28 |
3 | 9 | 42 |
4 | 12 | 56 |
5 | 15 | 70 |
6 | 18 | 84 |
7 | 21 | 98 |
I don’t know if you know this, but 56 gallons of water for a family of 4 is a LOT of water. It’s a barrel plus 4 gallons. That’s going to be hard for a lot of people to swallow (get it?), but I have good news…
You Already Have More Water than You Think!
Before you run out and buy a bunch of bottled water, let’s talk about the water that’s already in or near your house: (Let’s call this your ‘Baseline Water’)
- If you have a water heater, it probably holds between 30 and 60 gallons. Your water heater will have a sticker on it with its capacity.
- Every toilet you have will store at least one gallon in the tank. The tank holds clean water – the bowl is NOT clean.
- For every 100 feet of water pipes in your home, you have about a gallon of water. Depending on the size of your home and number of plumbing fixtures, the pipes in the walls of your home will have 5 gallons or more.
- You may have water in your water hoses outside, depending on where the hoses are stored. It’s easy to find out – go outside and pick up the hose from the middle – does water come out the end?
- If you have a hot-tub or pool in your home, in your apartment complex, or in your neighborhood it represents a significant source of water.
- Same goes for a nearby lake or stream.
How do I use all of this ‘Baseline Water’ that is already in or around my home? Water in your lines and fixtures (excluding your toilet bowl of course) is potable. That means you can drink it, but you have to be careful. If you lose access to running water and flush your toilet, that tank will not refill. Similarly, if you turn on the hot-water spigot after your home has lost water pressure, then it will drain the tank. The water in pools, hot tubs, lakes, and streams would need to be treated to be potable.
Also, and VERY IMPORTANT: If you lose water pressure for any extended time the utility pipes will start growing stuff. If your local authorities send you a Boil Water Notice then you need to follow their directions.
Here are a couple of options on how to think about this:
- Use the Baseline Water as your ‘Second Gallons’ – Remember I said one to two gallons per person per day. Buy bottled water for one gallon per person per day, and then use the other options for the second gallon. You drink the bottled water and use the other water for hygiene, cooking (maybe with extra boiling), etc.
- Use the Baseline Water to extend past the three day planning target. This is my strategy – I have two gallons of bottled water per person for a week, and then use other sources (Water heater, toilets, hot tub, lake) in case I need to get my own water for MORE than three days.
Treating Water to Make it Safe
Not all water is safe to drink. Water can contain viruses, bacteria, parasites, chemicals and other contaminants. Drinking untreated water can cause a range of problems, from short-term stomach issues to chronic disease. The water coming from your tap IS safe most of the time, but in some emergencies water pressure will drop and tap-water will grow dangerous bacteria.
You need to be prepared to treat water and make it safe. There are several ways to do this, and they vary in terms of convenience, cost, effectiveness, and speed:
- Boiling – Boiling water for 1 minutes will kill viruses, bacteria, and protozoic parasites. The good news is you don’t need a lot of special equipment to boil water. The bad news is you need fuel. If you want to purify lots of water, you need lots of fuel.
- A 20-lb propane tank has 430,000 BTU’s, so it will heat roughly 200 gallons (I’m assuming a lot of loss / inefficiency.) This is my first choice for boiling water. My only caveat is that I use propane for emergency heat. You’ll need a burner or a stove. Your grill will probably work, but won’t be efficient.
- A 1 gallon can (128 oz) of white gas will boil about 40 gallons on a popular (and efficient) stove. This is my second choice for boiling water. It’s more expensive, and I tend to use it more for cooking.
- Wood depends on the wood, how you build your fire, where you put the pot, and the weather. The good news about wood is there is probably a lot of it where you live, and it’s probably cheap. The bad news about wood is the smoke and ash.
- Don’t waste your battery boiling water. Yes, you can do it. Yes, I’ve done it and I wished I hadn’t. I wanted to see how much of my big battery it took. It took a lot, and I was only 3/4 of the way through my power outage. Now I save my battery for the fridge, lights, radios, and maybe a computer.
- Chemicals / Disinfectants – There are several good chemical water purification options on the market. Most chemical disinfectants will leave an after-taste. And my unofficial survey of American households (AKA my Guess) is that more people have stoves than have bleach. If you’re planning to use them before an emergency, you should buy them before the emergency begins.
- I personally like Katadyn Micropur tablets. They are reasonably priced, have a 5 year shelf-life, are easy to use, and kill most organisms that I’m worried about in the water I’d use. I have these with me when I leave the house. They’re in my truck and in my work backpack. I’ve used them on a lot of backpacking trips, and they work. The tablets are packaged in pairs, so the unused tablets stay fresh for the full 5 years.
- I’ve used Potable Aqua tablets before, and they are OK if you don’t mind the iodine taste. They’re cheaper than Katadyn Micropur, BUT their shelf life is only one year after the bottle is opened. I’ve heard that you can use Potable Aqua as a wound disinfectant as well, but YMMV.
- I’ve never tried a Steripen, but apparently it’s pretty whiz-bang. The science is certainly sound – it uses ultraviolet light to kill germs in your container of water. I’m just too cheap to pay that much to solve a problem I can solve with $.05 worth of bleach.
- You probably have unscented bleach at your house. If you don’t, you should. Stop buying the scented stuff. You can use unscented bleach to disinfect water. It won’t kill everything, but it will kill the most common problems in the US. You can use it to clean just about anything, if you’re careful. Use this table from the CDC to determine how much bleach you use. Let the bleach work for a full 30 minutes before you drink the water. Complete instructions are here.

- Filter – Filters are an OK option, but have some drawbacks: They are generally more expensive than bleach on a per-gallon basis, and they don’t all filter viruses. They also have benefits: No chemical aftertaste, and they are very portable. Many filters you can use while you are on the hoof – you don’t have to wait for chemicals to work. If you plan on using a filter to solve an emergency water problem, you should buy one before the emergency happens.
- I have a Katadyn Hiker Pro, and I recommend it. I’ve used it on several backpacking trips. Like most portable filters, it doesn’t solve for viruses. If you’re worried about that, consider adding some bleach to your filtered water.
- I also have several Lifestraws laying around. These are great because they are cheap and simple. Again, no virus protection but they are easy to use.
- I have the earlier version of this LIfestraw Mission. (They don’t sell mine anymore.) This filter DOES filter out viruses, and it’s designed for purify enough water for a family. And the price is pretty right.
- I REALLY want a Big Berkey. This is the Gold Standard in Water Prepping. It isn’t cheap but unlike the other items on this post, it takes care of pretty much anything. Not only does it filter viruses, but it is your best option (other than reverse osmosis) to get rid of many contaminants – lead, nickel, pesticides, arsenic to unicorns and acetone to Zima… The list goes on and on. I’d love to get my hands on a demo unit.
Emergency Water Prep At Home
In addition to all the previously discussed water in the house (hot water heater, toilet tanks, hoses and pipes), I keep emergency drinking water on-hand. The problem with emergency drinking water is that it is bulky and heavy. Most people (myself included) can only keep so much on-hand. This is one of those things where “You can never have enough” but “You don’t have room for an unlimited amount.”
Here’s what I have on-hand for drinking water, pretty much every day of the year:
- 3-4 cases of bottled water. They’re like 3 bucks a case. Why don’t you have 3-4 of them sitting around? These are for drinking. Each case has 3-3.5 gallons of water, so 3 days of drinking water per person.
- Five 5-gallon bottles of water. These are the bottles that go on a bottled water dispenser. Your grocery store sells them for about eight to ten bucks. I usually cycle them (read: dump them out and return the bottles for replacements) every 2-3 years. Each bottle has 5 days of drinking water per person.
- Nine Aqua-Blocks. Mine are 10-year shelf life, and I really don’t know why Amazon doesn’t carry them. I’ve ordered from Home Depot, but about 30% are damaged. They’re hard to get, but they’re great. This is our last round of defense before we start purifying water from other sources. Each one provides about 2 days’ drinking water supply for one person. ‘
So in total, I have about 50 gallons of drinking water at my house. This means I have 12.5 days’ worth of drinking water for my family of 4. Total cost: About $250.
I also have a Hot-Tub. I realize that not everyone has a hot-tub, and I realize that it is a huge convenience in many ways. One way my hot tub is a convenience is that I have tons of water in an emergency. No, I don’t WANT to drink it. But I know that our family COULD drink it if we had to weather an emergency. What is more likely is what happened in Winter Storm Uri – we used hot-tub water to flush toilets and rinse our bodies.
Our minimum for home preparation is three gallons of drinking water per person. Start there and build up.
Emergency Water Prep For The Road
I’m not going to cover a whole lot of new territory here – most of it was covered above. When I leave the house, I have water and I am prepared to purify water:
- I don’t leave the house without a full YETI Rambler. For one thing, I have a very active kid who never drinks water when he’s out and about. He’s always stealing my water. For another, San Antonio’s climate requires cold water. The Rambler keeps it cold.
- In my truck, I have a couple of 1-liter water bottles stashed under the back seat. I usually have 4-6 small single-serving water bottles in the doors.
- Also in my truck, I have a ‘get-home’ bag. It includes among other things:
- When I travel, I carry:
- A LifeStraw.
- A 24 Oz Hydroflask. I chug it right before I walk through airport security and then I refill it at the first water fountain AFTER airport security. There are cheaper water bottles, and when I lose this one I might use a cheaper one. But for now, I’m pimping the Hydroflask.
Emergency Water Checklist
Your goal should be one to two hours per person in your household .The minimum is 3 days, but you should start building up to a week's worth of water. 14 gallons per person is recommended.
Materials
- Bottled Water
- Unscented Bleach
- Aqua Blox Shelf-Stable Emergency Water
- LifeStraw Personal Water Filter
- LifeStraw Mission
- Katadyn Hiker
- Katadyn Micropur Tabs
- Yeti Rambler
- Hydroflask
Tools
- 5-Gallon Bucket
- Water Hose
- Igloo Water Can
Instructions
- First, you need to calculate how much water you need per person in an emergency.
- Second, take a look at how much water is already in your house, in toilet tanks, hot water heaters, etc.
- Third keep some bottled water on-hand. Those cases of bottled water are convenient and cheap. We try not to use them for day-to-day, but we always have a few cases.
- Next get some longer-term water options. I like Aquablox.
- Figure out how you're going to make water safe after your bottled water runs out.
- Consider moving water around - cups, bottles, buckets, hoses, and cans.
- Finally, get some filters and/or purification tablets for while you are 'on-the-go.'
Notes
- I won't recommend something I don't own and use.
- The items on this list are more expensive than other options, but they're build to last. I'd rather buy it once and pay extra so I can count on it when I need it.
- As an Amazon Associate I earn from qualifying purchases.
You can also take a look at our checklist page for more comprehensive checklists.
Feature Image: Econt, CC BY 3.0 BR, via Wikimedia Commons
[…] Many solutions to these scenarios have mass and take space. As previously discussed, our minimum planning target is one gallon of water per person per day. For a family of 4, that’s 28 gallons a week. Consider a 5-gallon bucket. You know what that […]