How do I report an algal bloom?

Every year algal blooms occur on a few lakes in Maine. The warm water temperatures and long sunny days make ideal conditions for algae to grow. Some blooms can be very intense, changing the entire lake to a bright green color. If you see a very noticeable discoloration develop in the water and it’s not a common lake event, please give the DEP a call.

Sabattus Pond algae bloom

Call (207) 287-7688 or (800) 452-1942. Ask to speak to the "on-call" person in the Division of Environmental Assessment. Or send an email to

When reporting a potential algal bloom, try to get on the lake and look around in several places including the deeper areas, to see what the bloom looks like. If you can, take pictures of the bloom and send them to the email above. These observations will help you provide important information for DEP staff.

Be prepared to answer as many of the following questions as you can.You don't need to answer all these questions to report a bloom, but every detail can be helpful.

  1. Name of the lake and town.
  2. Name, address, phone number of person reporting.
  3. If you can, take pictures and email them to us.
  4. When did this start? How long has the condition persisted?
  5. Is the bloom mixed in the water or is it attached to plants, rocks or other structures? If it is attached, describe the size and color of the growths. Are they stringy or jelly–like or like cotton candy?
  6. If mixed in the water, what are the color(s) of the water and how intense are they?
  7. Is the water turbid (cloudy) or is it full of particles you can see with the eye?
  8. Was the bloom concentrated in certain areas (especially in downwind coves) or was it throughout the lake?
  9. Is there an obvious odor? (describe)
  10. Is there a surface scum?
  11. Have you seen anything like this before (or heard of similar reports in past years?)
  12. If you are a volunteer monitor, what was your most recent Secchi reading for the lake (and the date)?

For more information on blooms:

Visit the DEP Algal Blooms in Maine Lakes Page

The U.S. EPA has a pair of apps for reporting and checking the status of blooms throughout the country. These apps are still under development, and any lack of information about a specific lake should not be taken to mean that there are no harmful algal blooms (HABs) present. These apps are BloomWatch and CyAN. While the apps are useful, whether or not you use the apps, always report a suspect bloom in a Maine lake to the Maine DEP using the contact information on this "Report Blooms" page.

If you are interested in monitoring your lake, contact the Lake Stewards of Maine at (207) 783-7733, or check with the town your lake is in to see if there is a local lake association. You can also visit the Lakes of Maine website for more lakes information and data.