Toddler drownings are on the rise nationwide — with boys accounting for nearly two-thirds of the victims, US Sen. Chuck Schumer said Sunday, urging the federal government to probe the troubling trends.

In 2016, 463 children ages four or younger drowned, up from 420 in 2015 and 417 in 2014, according to data from the federal Centers for Disease Control and Prevention data and cited by the senator.

“Amidst the most popular months for swimming and the dog days of summer that find more and more kids in and around pools and other bodies of water, we must sound the alarm on this trend and demand new action from the federal government,” Schumer said in a poolside press conference in John Jay Park on the Upper East Side.

“When it comes to the dangers of drowning, who is playing the lifeguard? Not the federal government,” Schumer said. “I’m blowing a lifeguard whistle on the dangerous trend.”

Schumer also drew attention to a second startling drowning statistic: the pronounced gender disparity of victims.

Of the 2016 deaths, 66.1 percent were boys, according to the data, the most recent released by the agency. The figure actually represents a decline from a staggering 68.6 percent in 2015, but it still needs investigation, Schumer said.

“I request that the CDC investigate the main causes of drowning in this young population, as well [as] study why boys are so much more susceptible to drowning than girls,” Schumer wrote in an open letter to CDC Director Robert Redfield.

Schumer couldn’t immediately provide an explanation for the disparity but noted in the letter that the trend indicated “that gender-specific behavior and activities plays a major role in drowning accidents.”

The senator praised the CDC for compiling the stats but urged the agency and other federal entities to do more with the information to help drive down the numbers of drownings.

“We are saying to the CDC and everyone else, ‘Get the word out,’” Schumer said. “Let parents know the protocols for safety, let parents know what could be done.”

Schumer asked the CDC to develop an outreach campaign for parents of young children — perhaps even conducted in hospitals for new parents — by Aug. 1.

His appeal comes nearly one year after the drowning death of twin 3-year-old boys on Long Island.

Sue Aurilia woke up one morning in July 2017 to find her boys, Anthony and Nicholas, dead in the backyard pool of the family’s new home in Melville.

“It is tragic accidents like this, of toddler kids, that put a giant hole in your heart and should spur us to do all we can at the federal level to keep such young lives from being lost to drowning,” Schumer said of the twins’ deaths.