A high level of suspended solids and an objectionable taste, odor or color in water can cause animals to drink less than they should. Surface water supplies to which livestock have ready access are always potential candidates for contamination. Shallow dug wells without good surface drainage away from the well may be subject to infiltration of contaminants. The presence of coliform bacteria in a well is an indication that surface water is finding its way into the well. In karst topography, sink holes, losing streams and porous soils may allow direct contamination of fractured rock aquifers.
Water can serve as a reservoir for many different disease organisms and toxins.
Stagnant water contaminated with manure or other nutrients may develop blue-green algae, which can poison livestock, causing muscle tremors, liver damage, and death. Farm pond water needs to be observed for the presence of algae and other harmful organisms during hot, dry weather. Leptospirosis and Fusobacterium are two bacterial contaminants that often use water and mud, respectively, as modes of transportation from animal to animal. Leptospirosis is spread through urine of carrier animals. This disease often manifests itself as reproductive problems.