Dissolved oxygen left in wells is promoted by competition as a concern. What is their foundation for such a campaign? HCT Well-Klean - 900 wells in 4 years and everyone realizing exceptional results. Groundwater contains dissolved oxygen, thank goodness because it's an essential component of life and healthy water. Stay tuned for our scientific data. Results based on science, chemistry, biology and physics. For a list of cities, other references or an example of our work, contact us.