U.S. Geological Survey discovers groundwater issues across the U.S.
The U.S. Geological Survey recently completed an assessment of more than 20,000 wells across the United States and in the District of Columbia. Findings indicated that untreated water in 25 states has a high to very high chance of containing potentially corrosive groundwater.
According to the report, the groundwater itself is completely safe for drinking, and it is the interaction of the water with piping that may cause an issue.
The presence of calcium carbonate and the level at which it is present are the main contributing factors as to whether groundwater is corrosive or not. This causes scaling inside pipes, which prevents water with elevated chloride-to-sulfate mass ration (CSMR) from becoming corrosive. With lower levels of calcium carbonate, scaling does not occur inside the pipes, which allows interactions of naturally occurring metals in the water with galvanic plumbing systems.
— USGS (@USGS) July 13, 2016
The problem with old pipes
Galvanic piping, especially that used prior to the 1930s, and some solder and other brass components labeled as "lead-free" that contained up to eight percent lead prior to 2014, can react with the corrosive groundwater, causing potential health problems.
The leaching of lead and copper may occur from corrosive water when it reacts with the piping and plumbing fixtures in homes, causing these metals to dissolve into the water. Corrosiveness is indicated by stains in sinks or on pipes that are bluish-green, pitting of or small plumbing fixture leaks, and metallic tasting water.
Problems more common in the Northeast
The Eastern seaboard, and most especially the Northeast, had the highest prevalence of potentially corrosive groundwater, followed by the Southeast and the Pacific Northwest.
The problem is more common in Pennsylvania and Virginia, where a higher number of people use private wells or cisterns. In Virginia, 19 percent of the 2,144 wells monitored had lead levels in excess of the Environmental Protection Agency's safe amount of 15 µg/L due to "lead free" components in plumbing systems. In Pennsylvania, bedrock geology is the main culprit for higher corrosiveness, and 12 percent of the 251 wells tested exceeded recommended lead levels.
According to the U.S.G.S., approximately 44 million people rely on private water supplies, and experts suggest that homeowners conduct basic testing to ensure the water they are drinking is safe. Tests should be conducted routinely to monitor the supply and eliminate potential issues from groundwater interaction with the plumbing system and fixtures.