We do research in the area of microbial ecology of man-made water systems, with a strong focus on biological activity in drinking water systems, cooling tower water, industrial and horticulture water. Our research focuses on biological activity that can be a foe or a friend to water quality. An example of the first is growth of opportunistic pathogens, such as Legionella pneumophila, non-tuberculous mycobacteria or Pseudomonas aeruginosa, in water systems. An example of the second is microbial degradation of chemical contaminants in biological active carbon or slow sand filtration during water treatment.