Why are there dark specs/staining in my water?

The Minnesota Department of Health (MDH) has recently developed guidance for manganese consumption in drinking water. Manganese is a mineral naturally occurring in rocks and soil which can be absorbed into water and food. Your body needs manganese to stay healthy, though like many other minerals, excessive amounts can cause complications with extended years of overexposure. A person who has a healthy liver and kidneys is able to excrete excess dietary/most manganese.

Drinking water guidelines:

  • Infants younger than one year – manganese levels no more than 0.1 mg/L
  • Persons one year or older – manganese levels no more than 0.3 mg/L

      (mg/L = milligrams per Liter)

Minnesota groundwater can naturally have levels of manganese higher than the MDH guidance. Public and private well owners are currently being notified of the new guidance’s. Manganese levels at water sources range from 0.01 mg/L (10 ppb) and 0.7 mg/L (700 ppb). Varying water sources are used and blended to produce the water distributed. Private well manganese levels are not monitored by the City. Common household water treatment filters and softeners may reduce manganese in your drinking water. The best way to identify those levels within your home is to sample and pay for an analysis. Laboratory analysis pricing is approximately $30. 

Accredited Local Testing sites: 

Water Laboratories, Inc.             Elk River            763-441-7509   

Traut Water Analysis Lab           Waite Park        320-251-5090   

Learn more by contacting (MDH) at health.drinkingwater@state.mn.us or directly at 651-201-4700 with questions.

The City is working with engineering consultants and MDH professionals for plans to reduce the manganese levels in the City’s municipal drinking water. 

These projects include:

1. Seeking additional water sources. 

2. Modifying well houses to incorporate water treatment.  

What can residents do?

Several things you can do to filter manganese out of your drinking water. Certain types of home water treatment devices remove or reduce manganese (some refrigerator water filters, pour-through pitchers, units that attach to faucet, water softeners, etc.).

If you already have a home water treatment device that removes or reduces manganese, you may want to test the water levels coming from the tap you use for drinking and cooking. This will give you a general idea of the manganese level in your water. If you choose to test your water, we recommend using one of the accredited labs listed on MDH’s webpage.

If you do not have a home water treatment device that removes or reduces manganese, you may want to consider installing one on the tap used for drinking, cooking and preparing infant formula. Bottled water is a short-term alternative. Look for bottled water that is not labeled “mineral water.” Treatment devices should be certified to remove manganese. All home water treatment units require maintenance. Visit the MDH webpage on Home Water Treatment to learn more.

The Utility Operations team flushes hydrants spring and fall to help remove any build up within the main lines. This high velocity water movement scours the lining of the city pipes and flushes out accumulations through the hydrant. Mixers are operated within the Water Tower to keep water age uniform and tower levels are adjusted seasonally to encourage frequent turnover resulting in fresher water.  

Show All Answers

1. What is my drinking water quality?
2. Why is my water rusty?
3. Why do I notice a chlorine odor in the water?
4. Why is there a metallic taste in my water?
5. Why does the water sometimes look milky?
6. What causes the spots on my dishes?
7. I have a water softener in my home. How much water hardness does my water softener need to be set at?
8. Why does my water smell like rotten eggs and how do I get rid of it?
9. Faucet Deposits
10. Why is my water green?
11. Is City water safe to drink?
12. Who else can I discuss water concerns with?
13. Sample Site
14. Why are there dark specs/staining in my water?
15. How do I turn off the water supply to my house in the event of a scheduled plumbing repair?
16. What is the small metal disk in my yard or driveway?
17. Is the City responsible for plumbing leaks?
18. Does my insurance company cover my service line repairs/replacements?
19. How do I report a water or sewer issue?
20. I've noticed the water pressure in my house has decreased over the years, why?
21. How do I flush my plumbing?