If your well has outlived its useful life, it should be properly sealed and replaced with a modern, safe well. When landscaping, keep the top of the well at least one foot above the ground surface. Make sure that the well cap is undamaged and securely attached to the well casing, and that any connections to the well stay watertight. Keep hazardous chemicals like paint, fertilizer, pesticides, fuels, and motor oil away from your well. Water that has become contaminated by human or animal wastes can transmit a variety of infectious diseases, including dysentery, salmonellosis, hepatitis, and giardiasis.
Symptoms vary, but nausea, vomiting, and diarrhea, with or without fever, are most common.
These bacteria do not usually cause disease themselves, but their presence indicates that surface contamination has found its way into the well and disease organisms may also be present. When total coliform bacteria are found in well water, the water should not be consumed without boiling, and the well should be disinfected. For more information, see Bacterial Safety of Well Water and Well Disinfection . Nitrate is a common contaminant of Minnesota groundwater. Elevated levels of nitrate are often caused by run-off from barnyards or feedlots, excessive use of fertilizers, or septic systems.