My water leaves a black stain in my fixtures. What type of testing should I have?

Manganese. This is a common naturally-occurring mineral in the Willamette Valley. It is a nuisance factor in water, not a health hazard. This test can be performed individually or with the Water Treatment Package or the General Naturally-occurring Minerals and Toxic Metals Package under Packages on this web page. It is also included in the Water Irrigation Package.