How Many Ounces in Drinking a Gallon of Water a Day?

Let’s get straight to the point: There are 128 ounces in a gallon, so to drink one gallon of water a day, you would need to drink 16 eight-ounce glasses. It seems like an impossible task, but a 2008 study from the journal Obesity found that drinking more water each day can help support weight loss efforts. Using a calorie tracking tool like MyPlate is also a great resource to help you lose weight.

According to another 2009 study by Obesity, people who drink a few glasses of water before a meal tend to consume 75 fewer calories in this setting. While that amount may not seem impressive at first, study author Brenda Davy, Ph.D., says it can result in losing 10 pounds or more in a year.

So what does it look like to drink a gallon of water a day? Ounce for ounce is too much fluid to swallow and too much trip to the bathroom—but when it’s spread out throughout the day, it’s an achievable goal.

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How Much Water Should You Drink Per Day?


How many ounces of water you should drink each day depends on several factors, including your body weight, activity level, and current health status. While there is no magic glass of water to drink in a day, many health officials recommend using your thirst as your guide.

If you eat lots of fruits and vegetables and drink water-containing beverages, you will meet 70 percent of your water needs through your overall diet. While most of this amount comes from the beverages you drink, there are some estimates that we get about 22 percent of our water from food. This is good news, especially if you have trouble sipping water throughout the day.

But in case you need some precise numbers to guide your water intake, the National Academies of Sciences, Engineering, and Medicine has determined that an adequate daily fluid intake is:

  • Approximately 15.5 glasses (3.7 liters) of liquid for men
  • About 11.5 glasses (2.7 liters) of fluids per day for women

Additionally, the Institute of Medicine recommends that a healthy adult drink an average of 78 to 100 ounces (about nine to 13 glasses) of fluids per day.

How Many Ounces in Drinking a Gallon of Water a Day?

Ounce to Gallon Conversion Rate


Water is often referred to as an ounce, especially when talking about how much you should drink in a day. But what happens when the bottle you use is a gallon? How do you convert ounces to gallons? First, let’s review how many ounces are in a gallon:

  • 128 fluid ounces = 1 US gallon
  • 160 ounces (UK) = 1 British gallon

If the idea of carrying water in a one-gallon plastic container doesn’t excite you, you may be wondering how many glasses it takes to make one gallon of water. A typical glass of water is eight ounces. If you use the same size glass, you would need to drink 16 glasses (8 ounces each) of water each day to reach one gallon.

How to Drink a Gallon of Water a Day


Step 1: Chug Water When You Wake Up

Drink two glasses of water right after you wake up. Make sure each glass holds approximately eight ounces of water. An easy way to accomplish this is by filling a 16-ounce water bottle and placing it beside your bed each night so you always have easy access to water.

Step 2: Sip the Water While Getting Ready

Drink a glass of water while preparing breakfast and getting dressed. Then, during breakfast, have another glass to help you digest your food and start the day well hydrated.

Keep a designated 8-ounce glass of water that you use at home. Even garnishing can help you remember to keep drinking while making the experience a little more fun.

Step 3: Drink a Glass of Water with Lunch

Drink three glasses of water before lunch. If you’re exercising during this part of the day, drink additional water to replenish the reserves you expel through perspiration.

Drink two glasses of water at lunch. If your lunch is high in protein or fiber, this amount of water will also aid digestion. Wherever you go, remember to always have a full water bottle with you so you can stay hydrated throughout the day.

How Many Ounces in Drinking a Gallon of Water a Day?

Step 4: Improve the Flavor of Your Water

Consume at least three glasses of freshwater between lunch and dinner. Add a slice of lemon, some fresh mint, or cucumber slices to give your drink a refreshing taste and add variety, but don’t add sugar, which will reduce the effectiveness of any hydration you do.

Keep in mind that your total water intake may also come from other beverages. If you need a sugar-free alternative to water, consider a commercial carbonated water drink like La Croix.

Step 5: Drink Water with Dinner

Drink a glass of water while preparing dinner, then wash down dinner with two glasses of water. You should have consumed almost a gallon of water by this time. It’s important to drink most of your water until late in the evening to help reduce bathroom breaks during the night.

Step 6: End the Day by Drinking More Water

Instead of a sweet or nightly snack, drink a glass of warm water before bed, perhaps with some lemon or grated ginger, which can have a calming effect.

It’s easy to confuse thirst with hunger, which causes many people to overeat when they’re really thirsty. Finishing your day with a glass of water will reduce late-night eating and ease digestion throughout the night.

How Many Ounces in Drinking a Gallon of Water a Day?

Track How Much Water You Drink


Making a commitment to increase your total water consumption is only half the equation; you also need to monitor how much you actually drink each day. There are several ways to calculate your water each time you reach for a glass.

An easy, convenient way to keep all your information in one place is LIVESTRONG’s MyPlate Calorie Tracker. All you have to do is drink your water, enter the information into MyPlate, the program will do the rest. With handy charts and graphs, you’ll always know how close you are to your one-gallon daily goal.

If you’re tracking efforts show that you’re coming up short on your daily quota, consider trying a few of these tips:

  • Instead of a sip of water with your morning medication or vitamins, drink a full eight-ounce glass.
  • Heavy coffee drinker? Have a full serving of water between mugs.
  • Do the same when you’re drinking alcohol, alternating cocktails or beer with a full 16-ounce pub glass of water (which counts as two servings).
  • Drink 20 ounces of water two hours before a workout, drink about 10 ounces every 15 minutes of the workout, and another eight ounces as soon as the workout completes.
  • Feel hungry at the 3 pm slump? Have a glass of water because you may just be thirsty.
  • Never leave home without a full reusable water bottle.
  • Order water with your meal at restaurants and save the cocktail for dessert, if you still have room.

The Health Benefits of Drinking Water


Your body needs water to survive. Plain and simple. But beyond the requirement to sustain life, water also has countless benefits that contribute to your overall health including:

Side Effects of Drinking Too Much Water


Even if you are concerned about your weight, do not drink large amounts of water, which can cause overhydration. In addition to people trying to lose weight, this can sometimes happen to endurance athletes who drink heavily in the belief that it will prevent dehydration.

Unfortunately, when taken in excess, overhydration can lead to hyponatremia, a condition characterized by low sodium levels in the blood. Symptoms include irritability, confusion, nausea, headache, and in severe cases, coma.

It can be difficult to know if you are overwatering, as there is no “one size fits all” recommendation for the amount of water you should drink in a day. A general rule of thumb for endurance athletes is to weigh yourself before and after a long training session. This can help you determine the amount of water you lose and how much you need to drink to replenish your body.

When it comes to dehydration, heatstroke, and overhydration, it’s best to let your symptoms be your guide and consult your doctor right away if you have any concerns.

What do you think?


How much water do you drink each day? Did you know the general rules for water consumption? Do you usually wait until you’re thirsty to drink water? Or do you constantly sip throughout the day? Have you ever tried drinking a gallon of water a day? Share your thoughts and questions in the comments below!

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