Ohio Algae Information for Recreational Waters

Algal blooms have become more noticeable in Ohio’s lakes, streams and rivers during the last few years.

Although most blooms are green algae and not harmful, there are some that are actually a type of cyanobacteria that have the ability to produce toxins – called harmful algal blooms (HABs).


Remember, you can still boat, fish and recreate in Ohio’s lakes, streams and rivers. Just be aware that HABs exist. We hope the information here will give you a better idea of what HABs can look like and provide you with the information you need to safely enjoy Ohio's waterways.

to learn more about harmful algal blooms and state park beach advisories.

Algal Toxin Results

From Lake Erie, Ohio state park beaches and public water supplies:
Excel file

Report a Bloom

If you see surface scum or something that looks like blue-green algae at a state park lake beach, report it to Ohio EPA by completing the Bloom Report Form (click here for a fillable form) and emailing it to HABmailbox@epa.ohio.gov.


For more information about harmful algal blooms, contact:
Public Interest Center, Ohio EPA
(614) 644-2160

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