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News from Acton Municipal Utility District: Discoloration

As had been discussed in a previous notice, there have been a few instances in which the presence of manganese has caused a slight discoloration in the drinking water.  While steps are being taken to remove the manganese, occassionally a concentration slips through the treatment process resulting in colored water.

Manganese is not a regulated constituent in water supplies and is deemed as a secondary standard by the EPA meaning elevated concentrations may result in discoloration and possible taste issues but does not pose a risk to health.  All other routine water quality sampling has not indicated anything that is known to pose a risk to health.  So while the water is discolored, the water is still safe.

The Acton and DeCordova areas are going to be the most affected, but other customers in our service area may also notice this issue.  The water may appear slightly brown, yellow, orange or green.  House filters may stain black or brown.  It is our understanding that in this situation the filter is only staining and the staining is not using up the filter.

It appears that as the temperatures have risen, Lake Granbury is beginning to de-stratify, which is the process in which cooler water at the bottom of the lake becomes warm and rises into the upper parts of the lake.  When this happens, manganese, which is found at higher concentrations at the bottom of lakes, is then stirred up into the upper level of the lake at which our raw water intake pumps are located.

Through ongoing plant maintenance and adjustments in the treatment processes, this condition is expected to be eliminated altogether in the near future.  We will continue monitoring concentration levels along with our other routine water quality sampling.  In the event there is an adverse change, we will notify the public.  As a final reminder, while the water is discolored, the water is still safe.

If there are any concerns or questions, please feel free to contact us.