Why is Lake Como water green?

Over time, phosphorus has built up in the lake — reaching levels as high as three-times the Minnesota state standard — causing algae blooms, fish kills, and strong odors mid-summer. Also problematic to Como Lake's water quality is the invasive aquatic plant Curly-Leaf Pondweed (CLP) that dominates the lake's ecosystem.



The iconic emerald or "green" hue of Lake Como is the result of several natural factors working in harmony. Firstly, as a deep glacial lake, the water contains fine "glacial flour"—minerals and silt ground down by glaciers—which remains suspended in the water and scatters sunlight, particularly in the green and blue spectrums. Secondly, the lake’s cleanliness and depth allow for the growth of specific types of algae and phytoplankton that thrive in the nutrient-rich Alpine runoff; when sunlight hits these microscopic organisms, it reflects back a vibrant green color. Furthermore, the surrounding lush, green vegetation of the Italian Alps often reflects off the surface of the clear water, intensifying the emerald appearance. While the water is generally very healthy, seasonal "blooms" can sometimes make the color more opaque or intense. The combination of high mineral content, healthy biological activity, and the physical reflection of the mountainous landscape creates the specific, deep green aesthetic that has made the lake a world-famous destination for centuries.

People Also Ask

Lake Como is one of the most beautiful places in the world. It has absolutely stunning views of the surrounding majestic mountains with their deep valleys running through. The mesmerizing clear lake water varies in color from light green to dark green/blue.

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The area around Lake Como has a rich historical heritage. It was a popular retreat for Roman aristocrats and later served as a place of inspiration for writers, poets, and philosophers. The region's history and culture have left their mark on the architecture, art, and traditions of the area.

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adders are found in the countryside, and water snakes are found in the water. But both are common, as any outdoorsy person knows.

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In fact, Lake Como always tends to be clement, despite being framed by snow-capped mountains, despite being so close to Switzerland. Palm trees and tropical plants thrive in its shielded climate, where the lake is so deep that it never freezes.

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Lake Como is generally quite safe at night. The area is well-policed and violent crime is relatively rare. That being said, it's always important to be cautious and aware of your surroundings, especially when traveling alone. Keep your belongings close and try to stick to well-lit, populated areas whenever possible.

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However, Como Lake's greatest water quality problem is excessive phosphorus, which has caused annual algal blooms and overgrowth that has further damaged the integrity of the lake.

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It does not have to be expensive, but can be if you want it to be expensive. Typically I pay abot €11 for lunch in a bar and about €15 for dinner in a trattoria for dinner in the evening (both including wine). Restaurants will be more expensive.

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The tap water in Lake Como is safe to drink and even quite healthy as it comes from the alps.

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Lake Como is fed primarily by the Adda, which enters the lake near Colico and flows out at Lecco. This geological conformation makes the southwestern branch a dead end, and so Como, unlike Lecco, is often flooded.

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