Pacific Northwest States Rate High For Corrosive Groundwater Potential

Aug 15, 2016

Credit Brian Bull

A review of over 20,000 groundwater sites by the U.S. Geological Survey (USGS) shows half of the nation’s states have high --to very high-- potential to become corrosive.  As KLCC's Brian Bull reports, this includes Oregon and Washington.

The most affected states are in the northeast and south, but both Oregon and Washington rate for “high prevalance” according to the data. 

USGS map showing states by their potential for groundwater corrosion.
Credit USGS

The USGS says untreated corrosive groundwater can dissolve lead from pipes, fixtures, and solder.

Terrence Conlon is a groundwater hydrologist with the USGS in Portland.  He says 200 wells in Oregon were assessed.  They were largely in the Willamette valley between Portland and Eugene.

“This would really be more of a heads up for domestic wells, rural folks who are in self-supplied households that are in the rural part and not supplied from a municipal water supply," he explains.

" And just because the water – through these indices -- suggest that it’s corrosive, doesn’t mean that it will be corrosive.” 

The indices Conlon refers to involve how much calcium carbonate is in the groundwater – which prohibits leaching of metals from plumbing – and what’s called galvanic corrosion.  That’s when the water has high chloride to sulfate mass ratio and low alkalinity.

Concerned well owners can have their tap water tested for lead and other contaminants. 

Sites across the United States showing groundwater sites and their corrosive potential, according to the Langelier Saturation Index.
Credit USGS

  The USGS report can be found here:  https://www.usgs.gov/news/new-study-shows-high-potential-groundwater-be-corrosive-half-us-states-0