Contaminants found in the home, such as lead-based paint, mold, and radon pose known health risks and are routinely evaluated by home inspectors and other professionals. Threats from pollution outside the home, such as groundwater and soil contamination, are often as hazardous and are garnering increased attention in residential real estate.

Risks to Homeowners and Homebuyers from Environmental Hazards

Pollutants such as hazardous waste from industrial sites, solvents from dry cleaners and petroleum from leaking tanks can seep into soil and groundwater and cause unhealthy living conditions. Likewise, chemicals in the ground can travel through the soil as vapor, contaminating indoor air. There are three primary risks:

• Exposure to contamination via groundwater, surface water, soil, or vapors can compromise human health;
• Contaminated property is usually devalued; many studies show that properties near contaminated sites are often devalued as well; such properties can become stigmatized;
• Homebuyers can be liable for a cleanup, even if they didn't cause — or know about — contamination, when it comes time to sell the home.

Common Causes of Environmental Hazards

There are many types of environmental hazards that vary by region across the United States. Some of the more common sources of hazards include:

• Leaking underground storage tanks and spills of toxic substances;
• Prior commercial, agricultural or industrial activity on or near the property (often going back to the late 1800s or early 1900s);
• Contamination from vapors or liquid that has migrated via underground plumes or groundwater (plumes can extend for miles);
• Illegal dumping of hazardous materials;
• Improper handling, treatment, or storage of hazardous materials.

What to do if Contamination is detected or suspected

When homebuyers or homeowners are concerned about contamination, there are a few simple steps that can be taken:

1. Test well water : If the property is served by a private well, make sure the well water is tested. If there are concerns about a nearby underground petroleum leak, make sure that the water is tested for volatile organic compounds (VOCs). If water contamination is detected, it can often be addressed by installing additional filtering systems.
2. Correct indoor air quality problems : If indoor air quality is being affected by vapors entering the structure from underground plumes of contaminants, a ventilation system can be installed. These are the same systems that are used to dissipate radon gas.
3. Look for obvious signs: Finally, look for signs that contamination could be affecting soil or water on or near the surface. Signs include patches of dead vegetation, strong odors, dark or oily soil, and oily sheen on the surface of water.