How to know if spring water is safe
From Audiopedia
To know if a spring is truly safe, start by finding the exact source of the water, where it comes out of the ground. Once you locate this source, ask yourself a few important questions. First, is this the true source, or is there a stream or other surface water that goes underground above the spring? If so, what appears to be a spring may in fact be surface water that flows a short distance underground. In this case it will likely be contaminated, or may flow only during the rainy season.
Next, observe if there are large openings in the rock above the spring. Large cracks or holes can allow surface water to enter the spring more easily. If the water appears muddy or cloudy after a heavy rain, that’s a sign that contamination from runoff might be a problem. Also, look around for any sources of contamination near or just above the spring.
Next, check if there is a possibility of contamination near or just above the source of the spring. This could include pastures for livestock, pit toilets, septic tanks, use of pesticides and fertilizers, or other human activity.
Finally, check the soil around the spring. If the soil is very loose or sandy within about 15 meters of the source, surface water can seep down through the soil and potentially carry contaminants into the spring.