It's been drummed into our heads to drink eight glasses of water a day. But a new study may be debunking advice we've been hearing for years.

All that water may not necessarily be adding any extra health benefits.

Health experts have said to drink 8 ounces of water, eight times a day because it's good for your skin, good for your organs and good for losing weight.

"Absolutely unable to find a scientific rational for it," Dr. Stanley Goldfarb said.

Goldfarb said he reviewed hundreds of clinical studies on the topic at the University Of Pennsylvania.

He said there's no solid evidence that the average, healthy person actually needs that much water.

There's also no evidence that water helps flush out toxins.

"Drinking extra water doesn't appear to increase the kidney excretion of any toxins, and in fact, most of us don't walk around with toxins accumulating in our body anyhow," Goldfarb said.

So where did the eight-glass-a-day idea come from?

"It grew out of popular literature, popular press, home remedies," Goldfarb said.

In fact, Goldfarb said the body does a very good job on its own, regulating how much water it needs.

"The thirst mechanism is very effective and anyone who experienced a hot day knows how thirsty they become. This is the body telling you how much water you need to take in. And when you quench that thirst, you've really taken in enough," Goldfarb said.

Of course, there are people who do have a need for more water.

They include athletes, people who live in hot climates and those with certain medical conditions like kidney stones and urinary tract infections

Doctors said it's not harmful if you have been drinking eight glasses of water daily.