The short version
Economists from the University of Rhode Island and the US Environmental Protection Agency asked whether Narragansett Bay’s water quality shows up in the prices of nearby homes. They used chlorophyll, a measure of how much algae is in the water, as their yardstick. Homes near the shore sold for less where algae levels were higher, and the effect faded with distance until it disappeared about 1,500 m inland. Buyers seemed to respond most to the worst summer episodes, not to average conditions.
What the researchers did
The team used hedonic analysis, a standard economic method that compares the sale prices of many homes to work out how much buyers pay for each feature, here the quality of nearby water.
- They studied single-family home sales in ten coastal Rhode Island cities and towns on the bay, including Providence, Cranston, Warwick, East Greenwich, Bristol and North Kingstown. Starting from statewide records for 1992–2013, they built a dataset of 27,040 properties and 40,433 sales.
- They matched homes to summer (May 1 to September 30) chlorophyll readings from 13 state monitoring stations and buoys for 1999–2013.
- They compared homes within 100 m of the shore, 100–750 m and 750–1,500 m with homes farther away. They tested whether typical summer chlorophyll or the worst readings (the top 10%, 5% or 1% of days) best explained prices.
- They then estimated how much home values would rise under hypothetical cuts in chlorophyll across the bay.
What they found
- Being near the bay is valuable. In one version of the model, homes within 100 m of the shore sold for about 32.5% more than comparable homes more than 1,500 m away.
- More algae, lower prices. Higher chlorophyll was linked to lower prices. The effect was strongest closest to the water, weaker farther away, and not significant beyond about 1,500 m. The authors conclude water quality likely has no significant effect on homes a mile or more from shore.
- The worst days matter most. The 95th-percentile chlorophyll level, a measure of the worst summer days, explained prices best. The authors suggest buyers react to
rare but highly discernable events, such as algal blooms, odors, and fish kills
(Liu et al., 2017). The paper recalls that in 2003 more than 1 million fish died in the bay when oxygen ran out. - Cleanup adds up. Across the study area, cutting chlorophyll by 10% would raise home values by about $18.24 million in total, by 25% about $45.52 million, by 50% about $90.97 million, and by 75% about $136.23 million.
- The link to nitrogen. Using an earlier published formula, the authors estimate that a 25% cut in chlorophyll corresponds roughly to a 57.5% cut in nitrogen concentration.
- Probably an undercount. The estimates cover only home values. They leave out recreation by people living farther away, recovery of fisheries and the value people place on a healthy bay they may never visit. The improvement scenarios are hypothetical, and monitoring stations are sparse.
What it means for Waquoit Bay today
CPWB argues that cleaner water helps protect shoreline property values in Falmouth and Mashpee. This study shows how that can happen in a New England estuary: nitrogen fuels algae, algae blooms bring murky water, odors and fish kills, and buyers near the shore pay less. Narragansett Bay’s long struggle with nitrogen is described in a 1998 Rhode Island report card, and the paper notes that a 2004 state law required major treatment plants to cut nitrogen loads in half compared with 1995–96 levels by 2008.
The dollar figures come from Rhode Island and should not be applied directly to Waquoit Bay. Narragansett Bay is far larger and more urban, its housing market is different, and most of its nitrogen comes from treatment plants and rivers rather than the septic systems that dominate here. What does carry over is the pattern: the homes closest to the water feel the effects of bad water most, and the most noticeable bad events seem to matter more to buyers than average conditions.
Read the paper
Liu, T., Opaluch, J. J., & Uchida, E. (2017). The impact of water quality in Narragansett Bay on housing prices. Water Resources Research, 53(8), 6454–6471. https://doi.org/10.1002/2016WR019606
License: © 2017 American Geophysical Union. All rights reserved. Because the article is not openly licensed, we link to the publisher’s copy rather than hosting it here. The article is also listed in the University of Rhode Island and University of Nebraska–Lincoln research repositories. The card image is a title card made from the citation.
Drafted with AI assistance from the linked source.
