COLUMBUS, Ohio (WCMH) — Inspectors are hard at work all year making sure local swimming pools are safe and healthy, but pool inspectors with the Columbus health department say this summer has been particularly busy for enforcement.

A chlorine shortage is to blame, and it has led to inspectors closing pools almost every day, said Meredith Mazzarella, coordinator for Columbus Public Health’s Water and Land Protection program.

All pools and spas used by more than four families in Columbus and Worthington — about 800, according to Mazzarella — must be licensed by CPH.

“For our outdoor pools, we try to get to them twice a summer at minimum. At indoor pools, we try to get to those three times a year,” she said. “There’s a lot more to a swimming pool inspection than just checking the water and taking a quick look around.”

Inspectors make sure lifeguards are certified, fences are properly installed, equipment works and drains are secure. There’s also a lot that goes into making sure water is clean: pumps must churn through every ounce of water in the pool in eight hours; filters must be maintained; and there must be adequate levels of chlorine, which serves as a disinfectant.

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Meredith Mazzarella, coordinator for Columbus Public Health’s Water and Land Protection, demonstrates a swimming pool inspection at Maryland Swimming Pool in Columbus, Ohio, on July 15, 2021. (Steve Wainfor/NBC4)

“There’s a chlorine shortage that’s causing a lot of people to either not be feeding enough chlorine in the pool, because they’re trying to make do with a small amount of chlorine,” Mazzarella said. “Or they just don’t have any, but they’re keeping the pool open.”

The shortage is due to an increase in demand caused by the COVID-19 pandemic, Mazzarella explained, as homeowners rushed to install backyard swimming pools. A Louisiana chemical plant that served as a top supplier of chlorine caught fire last August, also contributing to the shortage.

The map above shows the latest inspections for pools in Columbus as of Thursday. The Franklin County Health Department includes hundreds of pool inspections in its database for locations across the county. Delaware County also keeps an easily accessible database.

As of Thursday afternoon, 19 pools in Columbus were closed, and 13 of them were closed due to low disinfectant. None of the closed pools are public.

Aloft Columbus University District1295 Olentangy River Rd7/13/2021Low Disinfectant
Autumn Springs5500 Floral Circle S7/6/2021SVRS
Brittany Bay Apartments4365 Bayshire Rd6/24/2021Low Disinfectant; SVRS
Brookview At Noble568 Carpenter Ridge7/14/2021Low Disinfectant
Commons On Kinnear (2 pools)1150 Kinnear Rd6/30/2021Low Disinfectant
Fairfield Inn9000 Worthington Rd4/13/2021Low Disinfectant; Main Drain
Hyatt Place Columbus Dublin6161 Parkcenter Cir6/17/2021Low Disinfectant
Jefferson Chase Apts860 Jefferson Chase Wy7/1/2021Clarity
Karric Place Of Dublin North3970 Brelsford Ln6/25/2020SVRS
Lake Eden Apartments5179 Dempster Dr7/14/2021SVRS
Sawmill Village6900 Sawmill Village7/12/2021Low Disinfectant; Clarity
Sheraton Suites Hotel (2 pools)201 Hutchinson Ave7/9/2021Low Disinfectant
Staybridge Suites115 Hutchinson Ave7/8/2021Low Disinfectant
Tall Oaks Apartments2300 Fitzroy Place S.6/8/2018SVRS
The Barn5451 Edward Farms6/28/2021Auto Controller; Main Drain
The Crossing At Grove City4454 Dogwood Tree Wy7/9/2021Low Disinfectant
Wilson Court Apts Llc3850 Habitat Dr8/12/2019Low Disinfection
*As of Thursday afternoon, July 15, 2021. List can change hour-to-hour.

“It’s mainly apartment complexes, the smaller pools. We are seeing a lot of closures for those this summer,” Mazzarella said. She noted that the list of closures can change multiple times throughout the day.

Pools that pass inspection display a green sign provided by CPH, and pools dealing with compliance issues that are being monitored by CPH display a yellow sign. Pools that have been ordered closed display a red sign.

Ben Orner contributed to this story.