The short version
Does nitrogen pollution cost homeowners money, not just eelgrass and shellfish? The Cape Cod Commission tested that question in Barnstable’s Three Bays, a nitrogen-impaired embayment a few miles east of Waquoit Bay. Comparing home sales from 2005 to 2013 with nitrogen readings from the bay, it found that each 1% rise in nitrogen was linked to an average 0.61% drop in home sale prices in the study area. The report argues that falling waterfront values shrink a town’s tax base and push more of the property tax load onto inland homeowners.
What the report covers
The Commission’s environmental economist combined sales records, water monitoring data, mapping and interviews with residents. The Three Bays watershed was chosen as a test case because, like much of the Cape, it has grown quickly and its bay is rated as impaired by nitrogen.
- Single-family home sales and assessment records in the Three Bays watershed for 2005–2013, the years when all the needed data were available.
- Nitrogen readings from 18 monitoring stations in the bay, turned into a map of nitrogen levels across the water for each year.
- A “hedonic” price model, the standard economist’s tool for pulling apart what each feature of a house is worth. It accounted for waterfront location, distance to the water and to a public beach, number of rooms, age, construction quality and year-to-year swings in the housing market.
- Four focus groups of long-time residents, organized with the local group Three Bays Preservation, plus a survey of 650 year-round residents Cape-wide about how they use the water.
What they found
- More nitrogen, lower prices. After accounting for the other factors, home prices in the study area fell an average of 0.61% for every 1% increase in nitrogen concentration. The report says this result was statistically significant at the 99% confidence level.
- The bay was getting worse. Nitrogen in Three Bays rose by about 15.8% over the 2005–2013 study period. Average levels had been well above the 0.38 mg/L threshold that the Massachusetts Estuaries Project set for healthy water in Three Bays for more than a decade.
- Small cuts, large sums. As an illustration, the report estimates that if nitrogen had been cut by just 3% in 2005, the average single-family home in the study area would have sold for $16,774 to $32,957 more in 2013. That adds up to $41 million to $80 million in sale value across the study area.
- Inland taxpayers feel it too. Lower waterfront values meant an estimated $295,715 to $581,019 in property tax burden shifting to other owners in 2013. Because towns make up lost revenue by raising tax rates, the report expects more of the load to fall on homes away from the water. It calls its inland tax estimates rough.
- Residents see the difference. Focus group members’ maps of where the water looked worst matched the measured nitrogen pattern closely. In the Cape-wide survey, 51% said they would change how they use the water if quality got worse, and 8% said they would consider leaving the Cape.
What it means for Waquoit Bay today
Three Bays, which borders the villages of Cotuit, Osterville and Marstons Mills, is a close cousin of Waquoit Bay. Both are shallow south-coast embayments with high-value waterfront homes and nitrogen problems driven by septic systems and lawn fertilizer. It is reasonable to expect that dirtier water also weighs on home values around Waquoit, Eel Pond and the Childs and Quashnet rivers. But the 0.61% figure was measured in one bay over one period, and it should not be applied to Falmouth or Mashpee homes as if it were a local price tag. The report itself warns that it could not control for everything that affects home values, and it says plainly that this study is not authoritative
(Cape Cod Commission, 2015). The effect around Waquoit could be larger or smaller.
The broader point holds up, though. Doing nothing about nitrogen has costs, and some of them land on every taxpayer in town, not just those on the water. The Commission’s 2015 Section 208 Plan cites this study when it weighs the price of cleanup. That is a useful counterweight when Falmouth and Mashpee voters are asked to pay for the sewers and other fixes needed to meet Waquoit Bay’s nitrogen targets.
Read the report
Cape Cod Commission. (2015, March 11). Water quality and Cape Cod’s economic future: Nitrogen pollution’s economic impact on homes and communities. Barnstable, MA: Cape Cod Commission. Prepared by Mahesh Ramachandran, Ph.D., environmental economist. No DOI. Official copy: capecodcommission.org.
License: Published by the Cape Cod Commission, a Barnstable County agency. No open license is stated, so we link to the Commission’s official copy rather than hosting it here. A short executive summary is on the Commission’s website. The card image is the report’s cover page.
Drafted with AI assistance from the linked source.
