Potential Hidden Substances in the Groundwater You Drink

The amount, cleanliness, and use of water supplies within our commonwealth are complex subjects.  A general understanding of some basic tenets about water can help guide our daily decisions and ensure that enough clean water is available for the many ways that we need and want to use this resource.

We are fortunate in Pennsylvania to have a lot of surface water (streams, lakes, etc). Depending on where you live, your water supply may come from this surface water, or our even larger supply of groundwater (water found below ground, stored in the tiny spaces between particles of soil and rock). Since we can’t easily see it, we often don’t consider how our actions impact groundwater supplies.

Groundwater can contain both natural and man-made substances.  Some naturally occurring substances may cause poor water quality. An example is hard water, which contains significant amounts of calcium and/or magnesium. These minerals build up when they are dissolved from certain types of rock and sediments as water moves in the ground. Iron, which can give water an orange color; and hydrogen sulfide, which causes water to smell like rotten eggs, are additional examples of natural water quality contaminants.

Man-made substances also can contaminate groundwater. Industry and agriculture are often seen as major contributors to water pollution, but even fertilizers and pesticides applied by homeowners have an impact. Road salt, leaking storage tanks (both above and underground), unmaintained private septic systems, cleaning products, and litter are a few more sources of water contamination.

The federal Clean Water Act and Safe Drinking Water Act (SDWA), both passed in the 1970s, were designed to reduce contaminants in both surface water and groundwater. However, the SDWA only sets standards for public water systems. Homeowners or renters who use private wells for their water supply are not protected by this act.

It is also important to note that Pennsylvania has no statewide regulations regarding who can drill a private water well and how it is constructed. Some local municipalities have established laws in these areas, but many Pennsylvanians remain at risk of water contamination from poorly sited, constructed, or maintained wells.  Water testing standards do not exist to ensure the cleanliness and safety of the water provided by private wells, either.  

Since we cannot see, taste, or smell many potential contaminants in water, regular water testing is recommended for private well owners and users. The basic tests which Penn State Extension recommends include annual checks for total coliform bacteria, every three years for total dissolved solids and pH, and a test for nitrates if the well is located near fertilized cropland or anyplace where manure or commercial fertilizer is applied.  Testing is also recommended if you notice an unexpected change in the color, smell, or taste of your water.   

The presence of coliform bacteria in drinking water might indicate that a pathway into your water exists for bacteria which can cause illness. High nitrate levels may result from contamination by fertilizers, manure, or human waste.   Total dissolved solids are minerals in water, such as salts, which are generally found in low levels in quality water. A low pH level in water can lead to the corrosion of your plumbing if your system contains any copper and/or lead parts, possibly resulting in leaks; or dissolve lead or copper into your water which can cause a variety of potentially serious health conditions.

Water testing should be completed by a DEP accredited laboratory. For additional information about possible water contaminants and a link to a list of these labs, visit Testing Your Drinking Water.  The Pennsylvania Department of Environmental Protection website also contains additional information to assist property owners with the management of private wells.