Water Quality Monitoring

Since the 1930s, GELIA has actively monitored the quality of our water, with testing at different times throughout the year, in cooperation with the University of New Hampshire. Historically, GELIA has been among the cleanest lakes of its kind. Increasing levels of cyanobacteria in recent years underscore the need for vigilance, with everyone doing their part to keep the lake clean.

Water monitoring has been carried out in recent years by Dave Lafond and Chuck Hodsdon. Results continue to show Great East to be an Oligotrophic or “Pristine” lake.

To put our water quality in perspective, our average Secchi disc readings in recent years in the main part of the lake were over 10 meters. This means that an 8″ black and white disc is visible in over 30 feet of water. Data from 450 of Maine’s 2000 lakes in 2008 found only 8 lakes which had an average transparency of 10 meters or more. Most of these were in Aroostook or Hancock counties where the lakes are likely to see a lot less stress than those in more populated areas. We need to continue doing everything possible to maintain this exceptional water quality.

In the fall of 2022, GELIA commissioned a report on the growing cyanobacteria problem in the lake, with recommendations on how we should continue to monitor and address the issues. A copy of the report is here.

Our online archive of past water quality reports is not complete, but these are the reports we have available:


















The staff of the Lakes Lay Monitoring Program at UNH made 4 visits to each of our four sites this year. In addition, we made one round of visits to our four sites October 2021.

The Secchi Disk transparencies over the summer at the 3 deep water sites averaged about 10 meters. That means that the 8″ black and white disc was visible to the naked eye through a scope at a depth of approximately 30 ft. We had a Secchi Disc reading of 14 Meters a couple of years ago, but readings in the 10-meter range place Great East Lake as one of the cleanest lakes in NH, and NH has some of the cleanest lakes in the country.

In addition, factors such as chlorophyll a at 1.5 mg/L, dissolved color is 10 CPU and bottom total phosphorus is 5.6 mg/l.

These measurements let us know that our lake continues to exhibit outstanding water quality.

GELIA Membership

Help Preserve Great East Lake for Years to Come

Our Favorite Photos of Great East Lake
Copyright © 2024 Great East Lake Improvement Association. All Rights Reserved. | Privacy Policy | Term & Conditions |