Oklahoma City’s Hefner Water Treatment Plant uses ozone to disinfect drinking water. Ozone is a chemical made of three oxygen atoms. It kills bacteria and viruses, and it makes metal contaminants easier to remove.

But the ozone treatment system at Hefner is nearing its expiration date, according to city officials. During the summer, OKC’s water consumption comes close to topping out its capacity.

So the city is upgrading it with a $44 million replacement system. The new ozone disinfection apparatus should be online by 2025, and it will be able to disinfect 30% more water than the current capacity.

The existing system will come offline twice as part of the replacement process — once this winter and once in December 2024. To keep the water clean during those month-long shutdowns, OKC will switch to another disinfection tactic: chlorination. That means the water will stay safe, but it may taste different or unusual.

This project is part of the nearly $2 billion in improvements OKC Utilities has slated for the next five years.