Here is an amazing CBS news story about the struggles of the Navajo People who rely totally on groundwater. No running water and indoor plumbing. They must store water outside. Luckily many Navajo people have a saintly woman to deliver water they call the Water Lady.
Can you imagine what life must be like relying on only 7 gallons of water per day? That is like only flushing a standard toilet twice per day. That's it - all you get for drinking, cooking, washing, etc!
When I worked for the U.S. Geological Survey on the Navajo Reservation conducting surveys of water resources, we found that groundwater was in very deep formations and the quality of water changed depending upon location. Water is very precious - especially on the reservation!
For more information on the water quality of San Juan Basin aquifers, check out some of my old USGS reports (there are over a dozen) or contact me at firstname.lastname@example.org.