The short version
Living near the water is worth something to homebuyers, and part of that value may depend on what the water looks like. Economists at the US Environmental Protection Agency tested this along Maryland’s part of the Chesapeake Bay, using nearly 230,000 home sales. In most of the 14 counties they studied, waterfront homes sold for more when the nearby water was clearer. Effects on homes set back from the shore were smaller and less consistent.
What the researchers did
The team used a standard economic method called hedonic analysis. It compares the sale prices of many homes to work out how much buyers pay for each feature, in this case clearer water, while holding other features constant.
- They used 229,513 sales of single-family homes and townhouses from 1996 to 2008, all within 4 km (about 2.5 miles) of the Bay’s tidal waters in 14 Maryland counties.
- Water clarity came from EPA’s Chesapeake Bay Program monitoring, mapped onto a grid covering the Bay and its tidal rivers. Each sale was matched to the average clarity of the nearest water over the spring and summer (March to September) before the sale.
- They controlled for many other influences on price, including house size and age, neighborhood characteristics, distance to cities and beaches, and the salinity of nearby water. They also compared one-year and three-year averages of clarity.
What they found
- Clearer water, higher waterfront prices. In 10 of the 14 counties, waterfront prices rose with clarity, and in 7 of those the result was statistically significant. In those seven counties, a 10% improvement in clarity was linked to roughly a one-third of a percent to 1.5% increase in waterfront home values. None of the other four counties showed a significant effect.
- Dollar values vary a lot by county. The authors estimated what a 10% drop in clarity (roughly 4 to 10 centimeters less visibility, depending on location) would mean per waterfront home. Estimates ranged from $2,576 in Calvert County to $26,497 in Talbot County, in 2010 dollars.
- Smaller effects away from the shore. For homes not on the water but within 500 m of it, effects were smaller and less often significant. The largest was $3,233 per home in Queen Anne’s County. In Anne Arundel and Charles counties, the effect reached out to about 2 km and 1.5 km from the water.
- The Bay is murky to begin with. Average clarity in the study area was equal to seeing only about 0.64 m (roughly 2 feet) down into the water.
- How clarity is measured matters. Three-year averages gave much larger estimates, some of them implausibly large, plus some results that pointed the wrong way. The authors place more trust in one-year averages.
What it means for Waquoit Bay today
CPWB argues that cleaner water helps protect shoreline property values in Falmouth and Mashpee. This study supports the basic idea: along most of Maryland’s Chesapeake shoreline, buyers paid more for waterfront homes where the water was clearer. Water clarity matters in Waquoit Bay too, where nitrogen-fed algae have clouded the water and helped wipe out much of the bay’s eelgrass (see why Waquoit Bay lost its eelgrass).
But these results come from Maryland, with a different housing market, a much larger estuary and sales from 1996 to 2008. They also varied widely from county to county, and several counties showed no clear effect. The study shows the kind of benefit cleaner water can bring to shoreline owners. Its dollar figures apply to Maryland, not to homes on Waquoit Bay. The authors’ broader point is that changes in home values are a real benefit that should be counted when weighing the cost of cleaning up a bay.
Read the paper
Walsh, P., Griffiths, C., Guignet, D., & Klemick, H. (2017). Modeling the property price impact of water quality in 14 Chesapeake Bay counties. Ecological Economics, 135, 103–113. https://doi.org/10.1016/j.ecolecon.2016.12.014
License: The final journal article is published by Elsevier at the link above. The PDF below is the authors’ earlier version, released as US EPA National Center for Environmental Economics Working Paper #15-07 (December 2015). The authors wrote it as EPA employees, so it is a US federal government work and is reproduced here unmodified from EPA’s website. EPA notes the working paper had not been through the Agency’s peer and policy review, and the published article may differ. The figures in this summary come from the working paper. The card image is the working paper’s first page.
Drafted with AI assistance from the linked source.
