Windsor Parks and Recreation is cautioning residents about the green substance that's recently been observed floating in Windsor Lake. It was first noticed near the shore by a staff member on July 19.

While the substance is identifiable to algae, the city is still waiting for test results to come back, which will determine whether it's toxic or not. Unfortunately, the toxicity of algae can't be identified visually, so it must be sent to a lab.

According to the department, the test results from the water samples should be returned to the city as early as July 27. In the meantime, Windsor Parks and Rec has posted advisory signs around the lake, in order to keep visitors aware and allow them to make informed decisions regarding their participation in lake-related activities. Algae could potentially cause illness in both humans and pets that enter the water.

It's common to see algae in the Windsor Lake, as well as in other bodies of water in Colorado, at various points throughout the summer. Algae can multiply quickly, especially during periods of prolonged heat and in stagnant water.

The Town of Windsor will continue to keep the community informed through updates to social media and on its websites windsorgov.com and recreationliveshere.com.

LOOK: Here are the 50 best beach towns in America

Every beach town has its share of pluses and minuses, which got us thinking about what makes a beach town the best one to live in. To find out, Stacker consulted data from WalletHub, released June 17, 2020, that compares U.S. beach towns. Ratings are based on six categories: affordability, weather, safety, economy, education and health, and quality of life. The cities ranged in population from 10,000 to 150,000, but they had to have at least one local beach listed on TripAdvisor. Read the full methodology here. From those rankings, we selected the top 50. Readers who live in California and Florida will be unsurprised to learn that many of towns featured here are in one of those two states.

Keep reading to see if your favorite beach town made the cut.