Water quality is of particular concern.
The geothermal waters are high in total dissolved solids and boron. Discharge of these constituents into the city sewer system is strictly controlled. Because the area has a famous reputation for its fine wine, surface discharge of geothermal fluid through the sewer system is not an acceptable alternative. Furthermore, surface and sewer discharge is a wasteful use of the resource and is likely to receive criticism from the mineral water bottling companies in Calistoga. Domestic water supplies are also limited.