Last year, there were 718 cases reported statewide, despite new regulations adopted in 2015 to curb the number of infections. The 2016 number was only slightly less than the year before, when 870 cases were reported. That spike was mainly due to an outbreak in the Bronx that killed 16 people and sickened 138 others. And it’s more than in 2014, when 647 cases were reported statewide, according to the CDC.

So far this year, according to the CDC’s Morbidity and Mortality Weekly Report, 66 cases of legionellosis, the respiratory infection that can lead to Legionnaires’ disease, have been reported statewide, including 36 in New York City.

The regulations, finalized last summer, require cooling towers be registered, inspected and tested for the Legionella bacteria. They also require testing of potable water systems in hospitals and residential health care facilities, where 57 percent of cases originate and which account for 85 percent of legionellosis-related fatalities, according to the state Department of Health.

“Consistent with the Department of Health’s experience and relevant research, current regulations are focused on the sources of Legionella which pose the highest risk to New York residents,” the department said in a statement.

According to the Alliance to Prevent Legionnaires Disease, a group that includes representatives from the cooling industry, the regulations don’t go far enough to prevent the bacteria from forming. Municipal water supplies, the alliance argues, should be more vigorously tested and the state’s aging water infrastructure should be upgraded.

“Trying to address this issue from some narrow single point is just not going to accomplish significant improvements,” said Brad Considine, the group’s director of strategic planning.

The state health department attributed the increase in cases over the years to heightened awareness of the bacteria and said it is willing to expand the regulations, if necessary.

Legionella bacteria is most commonly found in potable water used to shower or wash your hands, according to the CDC. The second-most common source is cooling towers. The bacteria also thrive in warm environments, making fountains and hot tubs susceptible. The bacteria becomes a problem when people breathe in small water droplets or when water is accidentally aspirated.

While most healthy people don’t typically fall ill after being exposed to the bacteria, smokers, people who have chronic lung disease or weakened immune system and those over the age of 50 can develop Legionnaires Disease, a type of pneumonia, according to the CDC.

While the city and state have taken an incremental approach to addressing Legionella, the Alliance to Prevent Legionnaires’ Disease is calling for more aggressive action.

“We’ve been recommending residual chlorine requirements at all points of [water] distribution,” Considine said. “Water can leave the treatment center and be fine and it can pick [legionella] up again later.”

Adding more disinfectant to water at different stages of the process and updating the infrastructure could cost billions.

Sen. Kemp Hannon, chairman of his chamber’s health committee, introduced legislation earlier this year to create a water quality institute that would review and make recommendations for the maximum levels of contaminants in drinking water.

The Long Island Republican also proposed legislation that would set aside $5 billion for water projects and infrastructure.

In an interview last week, Hannon said that there should be a “forensic look” at what’s causing outbreaks