You should treat water any time you are concerned with water quality. In normal circumstances, municipal water in the United States and most developed countries is perfectly safe to drink. However, there are several instances when water quality cannot be trusted and treatment is strongly advised:
- Water straight from natural sources such as rivers, streams or lakes, as water run-off from surrounding lands may be contaminated.
- Water from the tap when the water supply has been jeopardized by natural disasters such as floods, hurricanes, tornados or earthquakes. (Physical breaches can allow external contaminants into enclosed water systems and power outages can disrupt water pumping stations, allowing water pressure to slow or stagnate, creating risk of microbial contamination.)
- If local authorities announce a boil alert.
- When traveling to foreign countries with known water purity problems, especially Latin America, Asia, the Middle East and Africa.
Specific reasons for treating water vary in each of the situations listed above, but what they all have in common is the potential presence of a variety of microorganisms such as bacteria, viruses, protozoa, including giardia and cryptosporidium. These microbes make you sick by reproducing quickly and overwhelming your body’s immune system. Click here to see a listing and definitions of common microbes that can cause waterborne illnesses.