
According to the old rule of thumb, you're supposed to drink eight glasses of water per day (and some experts recommend even more). That can seem like a daunting task on some days, but here's the catch: You don't have to drink all that water. Roughly 20% of our daily H2O intake comes from solid foods, especially fruits and vegetables.
It's still important to drink plenty of water -- especially in the summertime -- but you can also quench your thirst with these 15 hugely hydrating foods, all of which are at least 90% water by weight.
It's still important to drink plenty of water -- especially in the summertime -- but you can also quench your thirst with these 15 hugely hydrating foods, all of which are at least 90% water by weight.

Cucumber
Water content: 96.7%
This summer veggie -- which has the highest water content of any solid food -- is perfect in salads or sliced up and served with some hummus, says Keri Gans, author of "The Small Change Diet: 10 Steps to a Thinner and Healthier You" and a consultant to Mindbloom, a technology company that makes life-improvement apps.
Want to pump up cucumber's hydrating power even more? Try blending it with nonfat yogurt, mint and ice cubes to make cucumber soup.
Health.com: The best foods for every vitamin and mineral
Water content: 96.7%
This summer veggie -- which has the highest water content of any solid food -- is perfect in salads or sliced up and served with some hummus, says Keri Gans, author of "The Small Change Diet: 10 Steps to a Thinner and Healthier You" and a consultant to Mindbloom, a technology company that makes life-improvement apps.
Want to pump up cucumber's hydrating power even more? Try blending it with nonfat yogurt, mint and ice cubes to make cucumber soup.
Health.com: The best foods for every vitamin and mineral

Iceberg lettuce
Water content: 95.6%
Iceberg lettuce tends to get a bad rap, nutrition-wise. Health experts often recommend shunning it in favor of darker greens like spinach or romaine lettuce, which contain higher amounts of fiber and nutrients such as folate and vitamin K.
It's a different story when it comes to water content, though: Crispy iceberg has the highest of any lettuce, followed by butterhead, green leaf and romaine varieties.
So when the temperature rises, pile iceberg onto sandwiches or use it as a bed for a healthy chicken salad. Even better: Ditch the tortillas and hamburger buns and use iceberg leaves as a wrap for tacos and burgers.
Water content: 95.6%
Iceberg lettuce tends to get a bad rap, nutrition-wise. Health experts often recommend shunning it in favor of darker greens like spinach or romaine lettuce, which contain higher amounts of fiber and nutrients such as folate and vitamin K.
It's a different story when it comes to water content, though: Crispy iceberg has the highest of any lettuce, followed by butterhead, green leaf and romaine varieties.
So when the temperature rises, pile iceberg onto sandwiches or use it as a bed for a healthy chicken salad. Even better: Ditch the tortillas and hamburger buns and use iceberg leaves as a wrap for tacos and burgers.

Celery
Water content: 95.4%
That urban legend about celery having negative calories isn't quite true, but it's pretty close. Like all foods that are high in water, celery has very few calories: just 6 calories per stalk. And its one-two punch of fiber and water helps fill you up and curb your appetite.
This lightweight veggie isn't short on nutrition, however. Celery contains folate and vitamins A, C and K. And thanks in part to its high water content, celery neutralizes stomach acid and is often recommended as a natural remedy for heartburn and acid reflux.
Health.com: 30 foods under 40 calories
Water content: 95.4%
That urban legend about celery having negative calories isn't quite true, but it's pretty close. Like all foods that are high in water, celery has very few calories: just 6 calories per stalk. And its one-two punch of fiber and water helps fill you up and curb your appetite.
This lightweight veggie isn't short on nutrition, however. Celery contains folate and vitamins A, C and K. And thanks in part to its high water content, celery neutralizes stomach acid and is often recommended as a natural remedy for heartburn and acid reflux.
Health.com: 30 foods under 40 calories

Radishes
Water content: 95.3%
These refreshing root vegetables should be a fixture in your spring and summer salads. They provide a burst of spicy-sweet flavor -- and color! -- in a small package, and more important, they're filled with antioxidants such as catechin (also found in green tea).
A crunchy texture also makes radishes a perfect addition to healthy summer coleslaw, with no mayo required. Slice them up with shredded cabbage and carrots, sliced snow peas, and chopped hazelnuts and parsley, and toss with poppy seeds, lemon juice, olive oil, salt and pepper.
Water content: 95.3%
These refreshing root vegetables should be a fixture in your spring and summer salads. They provide a burst of spicy-sweet flavor -- and color! -- in a small package, and more important, they're filled with antioxidants such as catechin (also found in green tea).
A crunchy texture also makes radishes a perfect addition to healthy summer coleslaw, with no mayo required. Slice them up with shredded cabbage and carrots, sliced snow peas, and chopped hazelnuts and parsley, and toss with poppy seeds, lemon juice, olive oil, salt and pepper.

Tomatoes
Water content: 94.5%
Sliced and diced tomatoes will always be a mainstay of salads, sauces and sandwiches, but don't forget about sweet cherry and grape varieties, which make an excellent hydrating snack, Gans says. "They're great to just pop in your mouth, maybe with some nuts or some low-sodium cheese," she says. "You get this great explosion of flavor when you bite into them."
Having friends over? Skewer grape tomatoes, basil leaves and small chunks of mozzarella on toothpicks for a quick and easy appetizer.
Health.com: 20 snacks that burn fat
Water content: 94.5%
Sliced and diced tomatoes will always be a mainstay of salads, sauces and sandwiches, but don't forget about sweet cherry and grape varieties, which make an excellent hydrating snack, Gans says. "They're great to just pop in your mouth, maybe with some nuts or some low-sodium cheese," she says. "You get this great explosion of flavor when you bite into them."
Having friends over? Skewer grape tomatoes, basil leaves and small chunks of mozzarella on toothpicks for a quick and easy appetizer.
Health.com: 20 snacks that burn fat

Green peppers
Water content: 93.9%
Bell peppers of all shades have a high water content, but green peppers lead the pack, just edging out the red and yellow varieties (which are about 92% water). And contrary to popular belief, green peppers contain just as many antioxidants as their slightly sweeter siblings.
Peppers are a great pre-dinner or late-night snack, Gans says. "We tell people to munch on veggies when they have a craving, but a lot of people get bored of carrots and celery pretty quickly," she says. "Peppers are great to slice up when you get home from work, while you're making or waiting for dinner."
Water content: 93.9%
Bell peppers of all shades have a high water content, but green peppers lead the pack, just edging out the red and yellow varieties (which are about 92% water). And contrary to popular belief, green peppers contain just as many antioxidants as their slightly sweeter siblings.
Peppers are a great pre-dinner or late-night snack, Gans says. "We tell people to munch on veggies when they have a craving, but a lot of people get bored of carrots and celery pretty quickly," she says. "Peppers are great to slice up when you get home from work, while you're making or waiting for dinner."

Cauliflower
Water content: 92.1%
Don't let cauliflower's pale complexion fool you: In addition to having lots of water, these unas
Water content: 92.1%
Don't let cauliflower's pale complexion fool you: In addition to having lots of water, these unas