Decorah's drinking water is safe, but....

The latest water quality report for the City of Decorah shows the city's water system meets all standards for the purity of its drinking water.

The annual report compares detected levels of chemicals in the water with approved levels.  Included are compounds such as chlorine, fluoride, copper and lead.  Those levels are far below "Maximum Contaminant Levels."

However, one water quality measure continues to need monitoring.  In testing for nitrates in the water during 2010, levels ranged from 2.8 parts per million to 8.2 parts per million.  The "Maximum Cntaminant Level" for nitrates is 10 parts per million.  Nitrates commonly come from runoff from fertilizer use in farm fields.  Periods of rain or even flooding wash off the fertilizer from the fields--and into the aquifers that make up the city's water supply.

Decorah Water Superintendent Dave Pahlas says nitrate levels average around 5 parts per million.  He says the city has never issued a warning for high levels of nitrate in its drinking water.

If the 10 parts per million level is reached, authorities would caution the public that very young children and the elderly might be at risk.