Intermittent Contamination of Drinking Water Sources

Water quality is not static and changes over time. Recontamination of fecal bacteria and intermittent contamination of E. coli bacteria can occur in wells, boreholes and other drinking water sources for a number of reasons:

  • Fluctuations due to rainfall and rainfall runoff into source waters and groundwater, especially after flooding events
  • Contaminated surface water runoff enters wells and surface water drinking water sources
  • Poor sanitary protection at the top of the borehole, no sanitary seal or well apron
  • Hand pump base doesn’t have a watertight seal where it attaches to the casing
  • Contamination at the well pump outlet (spout) from contaminated hands
  • Casing doesn’t extend far enough above the ground and surface water can enter well, defective well casing and/or liner
  • Shallow, open wells
  • Intermittent septic system intrusion and/or other transient fecal source
  • Collecting water with unwashed or contaminated hands and containers
  • Animals using the same drinking water source
  • Objects falling into the well or source
  • Open defecation

Here are other helpful resources on water quality monitoring.

Do you have questions about water quality testing? Contact us!