Nitrates in tap water

Dennis S. Gray's post states he has "10 - 20 ppm nitrates" in his tap water.
 ?????  EPA maximum allowable nitrates in tap water is UNDER 10 ppm.  If your
tap water is from a Public Water System, I think perhaps (1) your Nitrate
test is a bit less than accurate, or (2) The EPA would be VERY interested in
talking with the operator of your water utility!  (  :-)  )