Between Sequoia National Park And Fresno Is California's Popular, Dangerously Bacteria-Ridden Lake

When summer scorches California's Central Valley, cooling off at an inland lake is an unbeatable form of respite. About a 30-minute drive from Fresno, the underrated Central Valley city with quirky attractions, and a bit over an hour from Sequoia National Park, Avocado Lake has filled that role for many park visitors and Fresno residents alike. In fact, the lake was artificially created specifically to provide a spot for people to swim and fish in, encircled by a relaxing park with picnic areas and a playground. Unfortunately, though, the lake is one you should think twice about before swimming in, since it's faced repeated issues with bacteria contamination.

For two years in a row (2024 and 2025), high levels of the bacteria E. coli were found in Avocado Lake's waters. Most E. coli strains aren't themselves dangerous; instead, the presence of E. coli indicates that water is likely contaminated by feces and runoff that contains other, more harmful pathogens, according to the Clean Lakes Alliance. High levels of E. coli in the water are a common reason for lake closures and advisories. Swimming in contaminated water means you expose your body to potential pathogens, which mostly affect your gastrointestinal system, causing vomiting, cramps, or diarrhea. It's unclear exactly what's causing the recurring E. coli presence in Avocado Lake, though officials of Fresno County suspect it's connected to the King's River, which flows into the lake, potentially carrying in runoff or stormwater. Officials recommend that visitors avoid swimming in the lake when bacteria levels are high, though the levels vary from week to week.

As of this writing, Avocado Lake Park, including the lake itself, remains open to the public, and there's currently no advisory against swimming in the water. Still, bacteria levels fluctuate quite a bit; the lake is tested for E. coli weekly, with updates posted on a water quality map by the Central Valley Water Board. Since unsafe levels were detected for some weeks in 2025, it's a good idea to check the most recent status before going for a dip. Fresno County Parks Manager Chris Bernal told ABC 30 that if the E. coli levels are above a safe limit, "Do not drink the water. Do not cook with the water or use it to wash your dishes." Additionally, you should wash your hands thoroughly after coming in contact with the water.

Even if there's an advisory against swimming in Avocado Lake, there's no reason not to visit the park, water activities aside. There's a small parking fee, and the park is open from 7 a.m. to 10 p.m. in the summer months and 7 a.m. to 7 p.m. in the winter. On its 210 acres, you'll find picnic tables and barbecues, plus some dirt trails and a small sandy beach to sprawl out on. The park is just about a 30-minute drive from the Fresno Yosemite International Airport. If you're looking for some other options for a swim, head about an hour north from Avocado Lake to Shaver Lake, a secret spot in the California mountains for charming, lake town living.