Over the past decade, Pennsylvania has seen a huge increase in natural gas production due to technology advancements. Horizontal drilling combined with hydraulic fracturing, the process of cracking rock open deep underground to release the gas trapped inside, has made Pennsylvania the nation’s second largest natural gas producer. While a thriving natural gas industry is a boon for the state’s economy, well-documented accounts of air and water pollution have been associated with its development.

But do the benefits and risks of natural gas production impact Pennsylvania’s communities equally? In particular, while the broad economic benefits (more jobs, cheaper gas prices, etc…) may accrue to all members in the community, the local environmental impacts may only affect those living in close proximity to a shale gas well.

A recent paper published this month in the American Economic Review examines the impact of increased drilling activity on the property values of homes located in close proximity to a well, and in particular, estimates whether this impact differs for homes dependent on groundwater for drinking compared to those with publicly supplied water. To determine how property values for these different types of homes may be affected, EDF, working with economists from the University of Calgary and Duke University, utilized transaction level data across the state to conduct comparisons in three different dimensions simultaneously:

• properties very near a well to those further away;
• properties dependent on groundwater for drinking to those with access to piped water;
• and properties sold prior to a shale gas well being drilled with those sold after the well was drilled.

Furthermore, to account for the fact that many groundwater-dependent properties may be located further away from urban centers, the data were restricted to homes located near the piped water boundary. This helps eliminate differences in neighborhood characteristics that could affect both the price of the home and its proximity to a shale gas well.

The analysis determined that property values are impacted by proximity to a shale gas well, though results differ depending on the property’s drinking water source. Those with piped water can economically benefit from being very near a well (a value increase of 3 percent for properties within 1.5km of a well), potentially due to royalties and bonuses companies pay to develop on a homeowners land. However, the property values of homes that are dependent on groundwater and located within 1.5km of a shale gas well declined by an average of 13 percent. Importantly, the impact on both types fades with distance; showing that both the benefits (increased royalty payments) and costs (increased groundwater contamination risk) of proximity diminish as one moves further from shale gas development.

This analysis does not draw information from observed air or water contamination. Instead, the data reflects public perception and brings to focus two important observations.

The first is that oil and gas communities are becoming more aware of the environmental risks posed by development. Managing these risks is critically important, as nearly 10 million Americans live within one mile of a hydraulically-fractured oil or gas well.  Smart policies that improve operations and create more opportunities for public transparency are necessary to ensuring communities in close proximity to drilling feel adequately protected from the inherent risks of oil and gas development.

But the study also highlights another key issue – the economic and environmental consequences of oil and gas development (both positive and negative) do not impact communities evenly. There is a clear detriment to some populations – as there often is with any industrial activity.  And rigorous, economic and scientific analyses are important tools for helping policy leaders understand these discrepancies to respond effectively.

Economic research can provide insights into how markets internalize the environmental costs of economic activities, even if these costs do not have a monetary value associated with them (for example, you can’t buy greenhouse gases, but economic research has demonstrated that the social cost of a ton of carbon is around $40). This analysis demonstrates that the threat of drilling activity causing groundwater contamination – which has no market value – still has true costs. Rigorous economic analysis allows us to quantify these costs, leading to more informed policy decisions and better outcomes for both the environment and the local community.