Harvard researchers now recommend that people drink 30 to 50 ounces of water a day. Getty Images

Drinking eight glasses of water a day has long been accepted as sound health advice, but a new study suggests there is no evidence to support this recommendation. Instead, an article published in the Harvard Health Letter recommends drinking 30 to 50 ounces, or four to six glasses, of water a day.

But it is impossible to determine a single requirement for everyone, since recommendations depend on diet, weather and level of physical activity, according to the report. Expectant or breast-feeding mothers, people who are active and anyone who is sick should drink more water, the report says.

While the average person may not need to drink eight glasses, there are still plenty of reasons to be refilling your water bottle. Water helps keep body temperatures normal, lubricates joints and helps get rid of waste and bacteria, according to the Centers for Disease Control and Prevention. Water also helps cut down on all of the calories and sugar found in other beverages.

Researchers say water does not need to come from beverages alone. Fruits and vegetables with high water content, such as watermelon and cucumber, can help meet hydration needs. Cucumbers contain 96 percent water, while water makes up 92 percent of watermelon, according to health site Active.

“It’s really about fluids in general," Dr. Sharmeela Saha of the University Hospitals Case Medical Center told CBS.

Lack of water can prevent the body from carrying out normal functions, according to the Mayo Clinic. Even mild dehydration can cause a person to feel fatigued.

For those not getting enough water, the CDC recommends adding a slice of lime or lemon to their water to improve taste and carrying around a water bottle while doing errands.