Source water to fill water features may include local surface
water, groundwater, rainwater or tap water determining
the initial water quality. Subsequent contamination may
occur through fecal bird droppings, runoff from paved surfaces
(including e.g. dog feces), growth of micro-organisms in
water (Legionella and algae), and in some cases discharges of
combined sewer overflows (Schets et al., 2008). These contaminants
may include a variety of chemical and biological
contaminants, including pathogens and microbial cell debris,
such as endotoxins.