The U. S. Geological Survey (USGS) recently released a report titled “Potential Corrosivity of Untreated Groundwater in the U.S.”  I was intrigued because I guess I had never thought much about groundwater being corrosive.  So I decided to look up the exact definition of corrosivity. 

Where else would you look but Merriam-Webster, right?  Here is the definition I found. 

“Corrosivity:  The quality of being corrosive.”   Duh!  What kind of a definition is that? Using essentially the same word to define it? C’mon.

So I was forced to look elsewhere.  Browsing the internet, the best definition I found was from Montana State University (MSU).  “Corrosivity is a measure of how aggressive water is at corroding pipes and fixtures.”  It continued, “Corrosive water can mobilize lead and copper from pipes into drinking water and eventually cause leaks in plumbing.” 

Now that’s a little scary. 

With all the recent news from Flint, Michigan about lead poisoning from their SURFACE water supply, it’s scary to think the same thing could potentially happen to drinking water supplied by GROUNDWATER.  A brief clarification, however:  Corrosivity can be a problem for metal pipes but not for plastic pipes. 

Back to the USGS report:  It studied water from nearly 21,000 wells nationwide including public supply wells, private wells, other wells and springs.  A direct quote:  “The prevalence of potentially corrosive groundwater is rated very high in 25 states and the District of Columbia.  About 24 million people in these areas rely upon groundwater from private water systems for their source of drinking water.”  All but three of these 25 states are located on either in the eastern U.S. or the gulf coasts. Virginia is one of these states.

So why is the corrosivity potential high in Virginia and other eastern and gulf states?  It’s related to the groundwater chemistry.   

Groundwater in the eastern states for the most part contains fewer naturally occurring dissolved minerals than does groundwater from other parts of the country.  Sorry to be a bit technical, but concentrations of the anions carbonate and bicarbonate which are often derived from dissolved limestone generally are lower in the groundwater of the easterm and gulf states than in other parts of the country. 

In water from those other parts of the country where carbonate and bicarbonate concentrations are higher, these anions tend to coat the inside of pipes making them far less subject to corrosion.  In the eastern and gulf states this coating occurs to a much lesser extent. Therefore, in these systems, if lead (for example, from lead solder) and copper occur in the delivery systems, the chances are greater that these metals could be released into the water.

In Virginia, private groundwater systems are used by about 1.7 million people.  The Virginia Household Water Quality Program (VHWQP) run by Virginia Tech University provides information to homeowners about maintaining, testing and protecting private water systems. 

Dr. Kelsey Piper of Virginia Tech was quoted in the USGS Press Release: “Between 2014 and 2014, we found that 19% of the 2,144 private water systems sampled in Virginia exceeded the EPA lead action level of 15 micrograms per liter.”

If you live in Virginia and your domestic water supply is groundwater and if you have seen evidence of corrosion of if you have concerns, you may wish to contact the VHWQP.  They can be reached online at wellwater@vt.edu.  Their experts should be able to address your concerns and suggest actions if necessary.