Health Advisory Update: Drinking Water Advisory Rescinded
July 17, 2006
MADISON - Based on the results of tap water sampling at hundreds of residences in the Well 3 and Well 10 services areas and other areas served by the Madison Water Utility, the public health advisory for infants less than 6 months of age and individuals with liver disease to refrain from drinking tap water is no longer in effect, Director of Public Health Dr. Thomas Schlenker announced today.
Levels of manganese that have been and are being measured indicate that tap water is acceptable for daily consumption for the entire population. As always, discolored or dirty looking water that may occasionally emit from household taps should not be drunk or used for cooking. If such water persists, it should be reported to the Water Utility at (608) 266-4665, or email@example.com.
Analysis of 647 household tap water samples from the Well 3 and Well 10 areas collected since May 30th shows 88% with manganese levels below the aesthetic standard of 50 parts per billion (ppb), 11% above 50 ppb and 0.6% above the health standard of 300 ppb. Repeated re-sampling indicated that each of the three samples with levels above 300 ppb collected as part of the ongoing random sampling, as well as each of the five samples above 300 ppb collected in response to consumer requests, measured at acceptable levels of manganese.
This suggests that occasional moderate elevations in manganese in drinking water may occur when hydraulic changes dislodge sediment but that such elevations are not sustained. Thus, unrecognized long-term exposure to moderately elevated levels that might prove harmful to susceptible individuals would be unlikely to occur.
Newly instituted flushing techniques have proven to be effective at removing naturally occurring sediment from service lines. To ensure sustained safe and aesthetically pleasing drinking water, joint Madison Water Utility/Madison-Dane County Public Health ongoing monitoring and testing of well and tap water will determine where and when repeat flushing needs to take place. High manganese-producing wells will be considered for filtration or assignment to standby status.
Interim reports on drinking water will be shared with the public in the coming months and a full report and summary of results of manganese sampling for all wells and all areas of the community plus analysis relative to other contaminants will be published before the end of the year.
For more information about manganese and water quality, visit the Water Utility’s website at http://www.cityofmadison.com/water/manganese.html or call (608) 266-4651. Public health questions or concerns can also be directed to the Department of Public Health at (608) 266-4821.
- Dr. Thomas Schlenker, 608-267-4122