Smells like eggs, onions or similar odor.

Probably hydrogen sulfide. Check out these links for more info:

• Hydrogen Sulfide in Household Drinking Water, Cornell University (pdf)
• Household Water Quality: Hydrogen Sulfide in Household Water, Virginia Tech
• Drinking Water: Sulfates and Hydrogen Sulfide, University of Nebraska
• Hydrogen Sulfide in Drinking Water, Ohio State University

Orange, brown or black stains

Probably iron or manganese. See info at:

• Iron in Drinking Water, Pacific Northwest Extension
• Iron in Drinking Water, Wisconsin Dept. of Natural Resources
• Removing Mineral Deposits from Household Surfaces, NC Extension

White chalky spots on dishes and plumbing fixtures.

Sounds like hard water. The spots are calcium and magnesium. See info at:

• Drinking Water: Hard Water, University of Nebraska
• Household Water Quality--Water Hardness, Virginia Cooperative Extension

More information on testing and treatment

Try these links and also visit the Water Treatment page on this site.

• Home Water Quality Problems Causes and Treatments, Virginia Cooperative Extension
• Household Water Treatment, Virginia Cooperative Extension
• Water Quantity/Quality Fact Sheets, Cornell Cooperative Extension (12 different topics)