Discuss Manganese Concentration Levels in Ramsey’s Municipal Drinking Water

Purpose: 
The purpose of this case is to discuss the manganese concentrations produced by several of the city's municipal wells.

Background: 
On April 2nd  staff received notice from the MDH (Minnesota Department of Health) that  well # 1 and well #4  had been tested as part of the UCMR (unregulated contaminant monitoring rule) project in June of 2018. These wells had been found to exceed the MDH developed health-based guidance for manganese in drinking water of 100 ppb (parts per billion).  MDH guidance values are developed to protect people who are most vulnerable to the potentially harmful effects of a contaminant. A person drinking water at or below the guidance value would be at little or no risk for harmful health effects. For infants that are not drinking tap water or formula mixed with tap water, children over one year old, and adults, manganese in drinking water up to 300 ppb poses little or no health risk.

MDH uses and develops guidance values to protect people’s health from contaminants in groundwater used as a source of drinking water. Because these are guidance values, public water systems are not required to meet these values and some do not.

Joining us to explain these findings and their impact will be Brian Noma, who is the Public Health Engineer assigned to our water system and Anna Arkin who is also from the MDH, who specializes in Strategic Initiatives and Communications. 

Manganese is an unregulated contaminant which does not carry a legally enforceable Minimum Concentration Limit (MCL).  However, the City is required to include a note in our annual Consumer Confidence Report that several of our wells exceed the guidance limit for manganese.

To ensure all residents and businesses receive the same message, City Staff has developed a draft letter that can be mailed and posted on-line.  A draft copy of this letter is attached for Council review and discussion.
 

After we recieved the information on our managnese levels, we programmed our system to utilize the wells with the lowest manganese level to pump first, then to add capacity from the higher manganese level wells as needed. The wells with the lower manganese level could supply enough water to meet demand in colder/wet weather, but not over the summer months when turf irrigation significantly increases demand.  Another factor to consider is that our wells with low manganse levels produce water with high iron content so while we are solving one issue by reducing manganse concentrations, we are creating another issue by increasing iron concentrations. The utility department fields numerous complaints about the iron in our system on an annual basis,especially during times of low water usage. Water high in iron is orange colored in appearance and stains clothing, sidewalks and buildings, and plugs water meters shorting their replacement cycles.

While water softeners can help remove manganese, many people choose to not connect their water softener to pipes leading to faucets used for drinking water due to the taste.

Short, medium, and long-term options for addressing this issue willl be presented by Staff during the meeting.

Water Utility Funds will pay for the postage to mail the letters.

Based on Council Discussion

Based on Council Disscussion