For the last 60 years I've walked up to any and all manners of garden hoses hooked up to an outside valve, turned the valve open, allowed the water inside the hose to be flushed with fresh water, and had a drink from the hose. I've never been sick or felt the slightest discomfort from this behavior. I've never heard of anyone getting sick from the same. I have heard of some folks suffering from ulcers or heart problems related to stress.
Caveat: This method hs been used mainly in the Midwest, the West, and in New England. I have not tried it in the middle of the Okefenokee swamp.