Dr. Tim Flood has been tracking Arizona’s drowning rates since 1990, compiling reports that detail how many deaths occurred and where they happened. His annual reports are the barometer by which water-safety experts gauge their progress.

His research was the catalyst for the formation of the Drowning Prevention Coalition of Arizona and has spurred other organizations to initiate safety programs in an effort see those published numbers go down.

There was a time when drownings were assumed to be relatively rare in Arizona. After all, it is a landlocked, desert state. Then Flood began digging into the data.

“To my shock and horror, Arizona had a high drowning rate compared to the rest of the nation,” says Flood, Bureau Medical Director with the Arizona Department of Health Services.

Arizona still ranks fourth highest in the country for drowning deaths of children ages 1 to 4.

The culprit? Largely backyard swimming pools. There are an estimated 300,000 residential swimming pools in the Phoenix metro area alone. In 2016, the most recent year for which data is available, there were 175 pool-related incidences, either fatal or nonfatal, in Maricopa county, the state’s most populous county.

Figures such as these spark action. Early efforts such as drowning-prevention campaigns were largely aimed at parents.

Then the focus shifted to the life-saving importance of barriers around pools, by then a state law.

Now, organizations are trumpeting a new strategy.

“If I had to say one bright spot in how we’re going to control this issue, it’s the role of swim lessons,” Flood says.

In Arizona, it can be hard to find a home without a pool. So people with lower incomes often have pools without the means to afford swimming lessons. Obviously, that puts children at risk. Cities have responded to the call of action by offering discounted or free swim lessons for disadvantaged populations.

It’s hard to tell if they’re making progress. That’s because Flood’s data has become more accurate over the years. He used to depend on Phoenix-area fire departments to submit drowning reports. Now he uses hospital discharge data, which not only includes drowning deaths, but nonfatal incidents as well. He is now able to collect that information statewide. As a result, he’s seen a two- to threefold increase in the number of incidents from that data set.

Says Flood: “Our work is not done yet.”