What is the white residue on pots and pans after I boil water?
Santa Rosa tap water is Moderately “hard.” Groundwater sources contain calcium and magnesium hardness. The minerals in the water leave a conspicuous white residue or spots when water is boiled or evaporates. This residue is primarily calcium and is not harmful to human health.

View an Explanation of Water Hardness.

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1. Is our drinking water safe?
2. How will I know if my water is contaminated?
3. What is being done to protect the water supply impacts from the fire?
4. Is the water from my well safe to drink?
5. Where does tap water come from?
6. Why is the drinking water stored in large tanks on hillsides?
7. What is the best choice of drinking water: bottled or tap water?
8. My tap water sometimes has an odd taste and odor. Why?
9. What can I do to avoid taste and odor in my tap water?
10. Is my tap water safe to drink?
11. Does Santa Rosa fluoridate its drinking water?
12. Is fluoride in my drinking water safe?
13. What is water hardness?
14. What are the health effects associated with hard water?
15. What is the conversion factor for mg/L of hardness to grains per gallon of hardness?
16. How do I set my water softener correctly?
17. What is the white residue on pots and pans after I boil water?
18. If I am on a salt-restricted diet, will the sodium in drinking water hurt me?
19. What are total coliform bacteria?
20. What is E. coli? Where does it come from? How can water be treated to protect against E. coli?
21. How often do you test tap water for total/fecal coliform?
22. Why is water tested for total/fecal coliform only?
23. What can cause the tap water to be cloudy or milky?
24. What can cause tap water to smell like bleach?
25. Sometimes water coming out of my tap is brown or has sediments in it. Why?
26. What should I do if I turned on a faucet, and the water coming out is discolored?
27. What is wrong if I smell a rotten egg odor when I run water in the house?