Water Quality Report
The source of the water is a 3,809± foot deep well drilled into the Madison limestone formation, a lower-Mississipian/upper-Devonian formation of the Paleozoic era. Locally, "Madison-formation" wells are known to be high-producing, high-quality, artesian water wells. The Madison Aquifer extends throughout portions of Wyoming, Montana, North Dakota, South Dakota, and Nebraska and has been deemed the largest artesian aquifer in the United States.*
"The Madison limestone's 1,000-foot thick base forms the largest artesian aquifer in U.S., coursing beneath Montana east of the Rockies and across North and South Dakota, Wyoming, Alberta, Saskatchewan and the upper western portion of Manitoba. Its towering limestone features guided the travels of the most ancient people and more recently served as signposts for Lewis and Clark's journey." *
In the Powder River Basin of Wyoming and at the location of Crazy Woman Water the Madison formation and its aquifer is deep underground. In the Black Hills region of South Dakota the formation surfaces. There the exposed limestone is a hard, crystallized rock composed of calcium carbonate and calcium-magnesium carbonate. The Madison limestone is slightly soluble in rainwater and over time caverns and caves, including the well-known Wind Cave and Jewel Cave, have been carved by the infiltrating rainwater.*
*See http://www.wsgs.uwyo.edu/StratWeb/PowderRiverBasin/PowderRiverBasinPALEO.aspx and http://www3.northern.edu/natsource/EARTH/Madiso1.htm for more information regarding the Madison formation and aquifer.