Download the Full Report
We are pleased to share the 2025 Acid Rain Monitoring (ARM) Annual Report, prepared by the Massachusetts Water Resources Research Center (WRRC) at the University of Massachusetts Amherst and supported by the Massachusetts Department of Environmental Protection. This report presents the results of the 24th year of Phase IV of the project, including statewide analyses of pH, alkalinity, ions, and color trends across 147 water bodies monitored by 57 dedicated volunteers.
The report includes:
- A detailed summary of statewide sampling results and long-term trends (1983–2025)
- pH and alkalinity analyses for 147 sites statewide
- Ion and color results for 26 long-term sites
- Correlation and heatmap analyses illustrating chemical relationships among parameters
- Volunteer participation highlights and laboratory network overview
Volunteer Photo Gallery
Every year, hundreds of volunteers and community partners make the Acid Rain Monitoring Project possible.
Explore our 2025 Volunteer Gallery featuring photos from this year’s sampling day — April 6, 2025 — taken across Massachusetts in misty spring weather.
📸 View the 2025 ARM Volunteer Photo Gallery
These images celebrate the dedication of our volunteers, laboratories, and community members who continue to protect the health of Massachusetts’ lakes, ponds, and streams through their commitment to citizen science.
About the Project
The Acid Rain Monitoring Project, launched in 1983, is a long-term partnership between MassDEP and UMass Amherst’s WRRC.
Each spring, trained volunteers collect water samples from ponds and streams across the state to assess the effects of acid deposition on surface waters and to support science-based environmental policy in Massachusetts.
Learn more about the project and explore previous reports on our main Acid Rain Monitoring Program page.