This Is How Much Water You Should Keep In Your Car


I polled a few people in my local prepper group to determine how much water the average concerned citizen keeps in their car. After all, we preppers take emergency preparedness so seriously that we can convince ourselves we need every multitool in existence. It would follow that we would all have decent stores of water in our cars, I thought. Boy, was I wrong.

Today, I will talk at length about why and how we should be storing water in our vehicles. I’ll also explain why we should make sure the water is there when we need it and why we should worry less about saving it.

Plan to take at least a gallon of fresh drinking water with you whenever you drive, local errands and short commutes included. Factors such as increased distance and number of people will require keeping as much as a gallon of water per person for each trip.

Why You should keep water in your car

A list of 5 reasons to keep water in your car.

We live in a society of convenience. The closer we are to urban areas, the easier it is to stop by a convenience store or drive-thru to quench our thirst. We need to stop at gas stations on big trips, which is a great time to pick up a couple of bottles at inflated prices. Regardless of all this convenience, we must keep water in our cars.

There could be 50 gas stations within walking distance of every point of your journey, and you should still have water in your car.

If you only use your car to drive the kids to school, take water. Even if you only use your car to go grocery shopping once a week, you need water in your car. Even if you commute to work the same way every day and have never been late, take water with you.

Emergency Situations and Survival Needs

Emergency evacuations can happen anywhere, at any time. A forecasted storm is far more dangerous than predicted, and you are stranded. A major bridge is suddenly out, and traffic jams up every other route, keeping you in gridlock for hours. You may find yourself stuck on the freeway with a flat, and the tow truck expects to take at least two hours. There are a million reasons you should keep drinking water in your car.

In July of 2021, a rainstorm in Colorado caused multiple rock and mudslides and stranded several cars in a tunnel complex overnight. Though Interstate 70 had been closed earlier that day because of flash flood warnings, it had reopened to traffic just hours before the slides. How many of those people were traveling with enough water?

More recently, a weather event called an atmospheric river descended in Canada, north of Washington State. It washed out all roads heading into the greater Vancouver area, a reasonably large metropolitan area. It left people stranded for days waiting for rescue, and those traveling by car realized they needed to make alternate plans.

Dehydration Can Lead to poor Survival Outcomes

I like to stay hydrated. Most of us are chronically dehydrated and don’t even realize it. From both survival and emergency perspectives, going into a situation dehydrated is almost as bad as having no water with you when faced with uncertainty.

Access to water is essential during emergencies, but the best reason to keep water in your car is because you might get thirsty.

Ninety percent of emergency preparedness, survival, and prepping is learning to be prepared. Hydration is essential to keeping your brain and body functioning at peak performance.

We don’t have an endless supply of water when traveling, but that doesn’t mean we physiologically don’t need it. Our bodies constantly release water in one form or another, and we must replace that lost water before dehydration sets in because it can take days to recover from even the lightest case.

When faced with an emergency, your starting level of dehydration factors into how well you will work through your situation. Always drink the water you have to stay hydated. Don’t ration and save it.  

Related: Water & Survival: You Need This Much Each Day to Live

Avoid Convenience. Opt For Preparedness.

Stopping for water at a convenience store is expensive and not the most environmentally safe practice. Spending a dollar or two on a bottle of water doesn’t seem like a significant financial drain, but that bottle essentially costs a fraction of a penny when poured from your tap. The time it takes to recoup the cost of even the more expensive reusable water containers is only a month or two if the alternative was to buy a bottle or three a few times a week from the gas station.

Watch those drive-thrus, too. My kids are always trying to get us to stop at certain fast-food joints because they’re soooo thiiiiirsty. Because I keep fresh water (and all the snacks) in the car, we’re far less likely to spend money on overpriced water.

Your objective is to bring a fresh drinking water supply each time you drive. You can use tap water in reusable bottles if both water and bottles are clean. Refreshing your water every day is helpful and ensures that you will want to drink it in an emergency but storing sealed bottled water in your trunk is a good alternative.

How much water should you keep in your car?

We preppers and survivalists love to regurgitate the 72-hour mantra. The basics of emergency preparation tell us to store enough of everything to survive a 72-hour emergency. The rule of thumb is to store about three gallons of water per person to see you through the entire three days.

Applying that rule to your car trips would mean finding enough room in our vehicles to store three gallons of water for you, plus three more for each person traveling with you. If I am on a trip with my family, that means I need to store at least twelve gallons of water in my Outback. When it comes to keeping water in your vehicle for regular travel, the 72-hour adage is too much. We must strike a balance.

When we talk about having that much water on hand per person, we talk about having that much not just for drinking but also for cooking, cleaning, and personal hygiene. Since we’re traveling, we’re not doing a lot of cooking or cleaning. A roadside emergency might require basic hygiene, but not what we would need if we were in an emergency at home.

We can assume that we will drink 95% or more of the water used while traveling, so that’s where we will focus.

Your goal is to learn to calculate how much water you need to keep in your car. Consider where you plan to travel, the routes you plan to take, the time it will take to reach the destination, and how many people are traveling with you. With this information, you can determine the amount of water you should have stored in your car.

I have created a guide that divides trips into four zones. Read through each zone description to determine what zone your trip falls into and how much water you need. There is also a quick reference below the explanation of each zone.

Blue Zone

Your Blue Zone is your ‘Home’ zone. Travel spots within the blue zone should be primarily local. Think of the day-to-day stuff that requires travel to well-populated areas. Include your neighborhood and local shopping and entertainment spots. If your place of work is less than 10 miles away, include it. These are the places you confidently know.

Ideally, all places in the blue zone should have well-established, incredibly familiar routes. You should be able to walk home easily if the need should arise. No matter where you stop along your way, water should be available without walking for more than twenty minutes.

Your need for water is minimal in the blue zone, but I recommend always carrying an entire gallon of water in your car. You might think it’s a lot of water to keep in your car if you stay local, and you might not be wrong.

But this exercise aims to plan an emergency water supply in your car. A whole gallon of water will comfortably cover four people for a full day, regardless of why they can’t get home. Since water is still attainable everywhere, life-threatening dehydration isn’t a worry.

There are a few exceptions to the 10-mile blue zone rule. Traveling in extreme weather, over state lines, or over geographical or geopolitical separators should be treated like green zone trips. Read the next section for more information.

Green Zone

Your Green Zone is your ‘Familiar’ zone. Travel destinations in the green zone should should be limited to 150 miles or 3 hours of driving time from your home. My 150-mile radius is a guideline I use because most drivers are at least a little familiar with what lies 150 miles in most directions. Many of us can get to other towns or popular areas without a map. You can usually drive 150 miles in three hours, which is why day trips fall into this zone.

Your travel should take you through neighboring communities, trips to and from suburbs, or other well-populated areas. Include your place of work if your commute is more than 10 miles. If you can pick any point on your planned route and find a place for water within 25 miles or less, you’re in the green zone.

Your water needs are still low, but because this zone reaches out farther than your green zone, the possibility of needing extra water becomes greater. There is a significant increase in possible emergency stops on longer trips. Flat tires, a vehicle breakdown, extreme weather, and road closures are more challenging the farther away you are from your home zone.

Yellow Zone

Your Yellow Zone is much larger than your green zone, but in certain situations, you must treat trips within your 150-mile radius of your Green Zone like Yellow Zone trips.

Under ideal conditions, Yellow Zone trips are extended trips with pre-planned stops for shelter each night. Road trips driven entirely on established routes, regardless of length, fall in the Yellow Zone as long you plan to replenish your water supply at the end of each day. Think staying with friends or family or with hotel or campground reservations.

Shorter trips that typically fall in your Green Zone should sometimes be considered a Yellow Zone trip if there are other factors. Think about trips that take you across state lines, through areas prone to unstable weather, and on roads crossing geographical barriers.

Geographical barriers can be rivers with a single bridge in the area or a mountain pass. An accident could close a bridge, leaving you to wait for hours while the scene is cleared and investigated. Or the bridge could collapse, forcing you to backtrack and detour to the next bridge, adding another 100 miles onto your trip.

Mountain passes are notorious for avalanches, rockslides, and nasty accidents. Treat these routes with care, especially as our climate grows more unstable. Downed trees, unstable bridges, heavy precipitation, and extreme temperature changes can make travel difficult, if not impossible. Water isn’t the only item to pack in your emergency car kit, but it might be the most important.

The amount of water kept in your car for trips in your yellow zone should start with one gallon plus an extra quart for each person.

Red Zone

The Red Zone is the zone that covers trips most people don’t take. These trips take us off the beaten path through areas with little to no cell service and limited access to emergency services. Where is this primitive land? A road trip to Alaska might come to mind, but the reality is that there are many sparsely populated areas in America, and there are still reasons why some people need to travel through them.

But because cars are limited in space and even more so when traveling long distances, water becomes even more essential when traveling through Red Zones. Take as much as you can but take no less than three gallons for the journey, plus another gallon for each passenger.

And before you go, create a travel plan. Leave a copy with a trusted friend or family member who can alert authorities if you don’t check in by a particular time.


I have one parting tip for you. If you feel you need water stored in your car for long-term emergencies, avoid the emergency packets and cans sold online and touted by so many others in the emergency prep scene. Emergency water kits of this kind are made to part you from your money. They are expensive and not always reliable.

Be smart, and spend your money on something worthwhile, such as quality reusable water containers. Conservation of our lands demands we do what we can to minimize garbage and use what we have with purpose. Don’t create waste, and don’t pollute your backyard with single-use containers when possible.

A handy infograph depicting how much water you should keep in your car.
Click the image to download a PDF copy of this infograph