While ozone use is a relatively recent phenomenon in the US, it has a much longer history in Europe. Even in the US ozone has been in use for most of the last century. In fact, the largest concentration of drinking water treatment systems employing ozone are located in the Dallas-Fort Worth Metroplex. Major cities in the US and their close in suburbs using ozone include Los Angeles, Detroit, Dallas, Tampa, Boston, among many others.
From this beginning 1,000 ozone generators have been installed in drinking water plants around the world by 1999. Today there are approximately 3,000 ozone plants in the world today with over 1,500 in Europe and 260 in the US.
Below is a chart of ozone drinking water treatment growth in the US over the last 30 years: