Now that summer is almost here, experts are sounding the alarm about water safety, and they're not just talking about drownings.

"Drowning is the number three cause of accidental death in the United States," said Dr. Shawna Murphy, with the Lehigh Valley Health Network.

Experts say a near drowning can be just as dangerous, and even deadly.

Near drowning, also known as secondary drowning, is a phenomenon most haven't heard about.

But it can lead to serious health problems, including death.

That's why Dr. Shawna Murphy, of Lehigh Valley Health Network, urges all parents to listen up.

"You don't want to be that parent that puts their child to bed at night and something happens and you missed it," Murphy said.

Secondary drowning occurs when people inhale water in their lungs and otherwise appear fine.

"With near drowning we are submerged for a short amount of time, but it's enough for the larynx to close," Murphy said.

Experts also say it doesn't take a pool full of water to drown. In fact, just one tablespoon of water in your lungs could be deadly.

You could be long gone from the pool--minutes, even hours, could pass before you even notice a symptom.

"They can have wheezing, shortness of breath, coughing frequently," Murphy said.

Other symptoms include chest pain, fever and mood changes.

All symptoms could appear anywhere from one to 24 hears after the initial incident.

The symptoms themselves may not seem like a reason to rush to the emergency room, hence why near drownings often go unreported.

"Experts are estimating for every one drowning, we have 600 near drownings," Murphy said.

But Murphy urges parents to err on the side of caution and get their children checked out immediately if any water at all gets in their lungs.

"Unfortunately for near drownings, there's an estimation that 20 percent of people will have a neurological deficit from that incident," Murphy said. "Anytime someone has had a near drowning we need them to come in."

Murphy also emphasized the importance of preventing drownings.