The 2010 Annual Drinking Water Quality Report from the City of Blanco was recently mailed to residents of the city and those outside the city that purchase their water from the city.  With the exception of a violation of the total coliform bacteria standard last December, the report was very positive.  Actions have been taken to improve water-quality monitoring procedures and assess potential sources of contamination. 

What does this report mean and how does it affect drinking water?  Consumers of Blanco’s water might be concerned about a violation explained as “total coliform bacteria were found in our drinking water during the period indicated in enough samples to violate a standard.” 

Coliform bacteria are “indicator organisms” used to assess the microbiological quality of drinking water.  Coliform bacteria are found naturally in soils, and the presence of “total” coliform bacteria in drinking water indicates a source of contamination, potentially exposing consumers to pathogens.    Pathogens are organisms that may cause infection or disease. “Fecal” coliform bacteria are found commonly in waste material (i.e. feces) from humans, livestock, and wildlife, and the presence of fecal coliform bacteria in water samples indicates water contamination from one or more of these sources.  Escherichia coli (“E. coli”) is one of many species of fecal coliform bacteria; certain strains of E. coli can cause significant human health problems.  The 2010 Annual Drinking Water Quality Report indicated no detections of fecal coliform or E. coli bacteria in the water samples that were tested. 

Water operators in the City of Blanco, under the direction of the Mayor and City Council, are responsible for monitoring the coliform levels to keep our drinking water safe. They do this by monthly collection of water samples from outside faucets (a State of Texas regulation) at three locations representing the town.  The monitoring locations differ from month to month.  The city water plant uses a chlorine disinfection process to make the water safe to drink.  The amount of contact time between the water and the chlorine is critical as the river water passes through a settling process and then filters into the distribution system.   The report stated “operator error” was the cause for the violation in coliform levels.  Operator error could happen at either the collection site or at the water treatment plant.

The primary concern for the safety of Blanco’s drinking water is the quality of the source water as it enters the water treatment plant.  Our sources of drinking water include the Blanco River and Canyon Lake.  Natural and human factors within the Blanco and Guadalupe River drainage basins influence the quality of those water sources, including contamination with coliform bacteria.  Although it is impossible to control contamination by wildlife, it is possible for humans to reduce water-quality contamination by effective management of household and agricultural wastewater.  For the past six months, water sampled from the Blanco River met all State surface water-quality requirements.  During the same time period, all tests for total coliform bacteria in samples from the City of Blanco’s drinking water supply were in compliance with State standards.  

Citizens can do their part in keeping the river water as clean as possible.  Do not dispose of dead animals in the river or along the bank.  If one sees a carcass floating in the River or on the rocks contact the City Offices.  They will remove it.  Do not get rid of disposable diapers by leaving them along the River edge (or worse, tossing them in). Don’t use the river bank as an outhouse.  People do many things without considering the consequences of their actions.  Please, do not add to the contamination of the water you drink.