Quality of water in the northwest

The quality of natural waters, as judged by the dissolved mineral content, is quite varied throughout the Northwest. The concentrations of dissolved solids range from less than 50 ppm for many of the surface waters in Washington and Oregon, to several thousand ppm in the alkaline lakes of these states. On the whole, the quality of the natural waters is good but in some areas the waters have become unsatisfactory for many purposes, including irrigation, through contamination with wastes from industrial processes, which may include drainage from irrigated lands.