Copper in driking water webpage – Minnesota Department of Health
https://www.health.state.mn.us/communities/environment/water/contaminants/copper.html
https://www.health.state.mn.us/communities/environment/water/contaminants/copper.html
https://www.doh.wa.gov/portals/1/Documents/pubs/331-178.pdf
https://www.cdc.gov/healthywater/drinking/private/wells/disease/copper.html
http://www.wellwaterguide.net/copper-well-water.aspx