This city is not so beachy clean.

The Big Apple’s cleanest and filthiest shores along the Long Island Sound were revealed Tuesday as part of a disappointing report card — and most of the piss-poor performers are exclusive membership clubs.

Eight of the city’s 11 Sound beaches took home Ds or Fs when it came to being fecal- and pollution-free last summer, and a luxury stretch along Eastchester Bay was named the crappiest in the entire waterway, according to an annual survey by Save the Sound.

“I can’t say that that’s completely surprising. New York City is one of the greatest cities in the world, of course — but it’s incredibly developed, it has a combined sewer system and those factors alone present some very big challenges to water quality as it pertains to swimming,” Peter Linderoth, the director of healthy waters and lands for Save the Sound, told The Post.

The annual report card rates how healthy the waters from the Hell’s Gate Bridge to Block Island are for human swimmers by randomly testing for bacteria and pathogens throughout the summer.

Only three Fs were handed out in 2025 — and all were claimed by The Bronx.

The beaches at White Cross Fishing Club, American Turners and Trinity Danish Young People’s Society were named the filthiest in the entire sound after numerous water testing visits determined that bacteria were splashing in the water just as much as club members.

White Cross Fishing Club performed the worst after failing 39% of its 57 random water quality samples — which detected pathogens associated with untreated sewage, improperly disposed of dog waste, goose poop or polluted stormwater.

The nearby Danish American Beach Club and Manhem Beach Club fared only slightly better, with each earning a D- and D, respectively.

The Schuyler Hill Civic Association, Whitestone Booster Civic Association, and Douglaston Manor Association Beach, which pepper the East River near Little Neck Bay, also earned varying levels of Ds for last year.

Just three beaches earned top marks in 2025, and all are clustered near City Island.

Orchard Beach — the city’s only public beach on the Sound — and West Fordham Street Association came out on top of the class with B+ scores, while the nearby Morris Yacht and Beach Club each skated by with a B.

The disappointing scores shouldn’t be shocking, according to Linderoth, who noted how close each of the dirty beaches is to combined sewer outflows — which dump untreated sewage mixed with rainwater into open water during storms.

“2025 was a relatively drier summer with about 16 inches of rain, but that’s still enough for stormwater impacts to manifest. Discharging raw sewage and rainwater — albeit permitted, because it’s a known thing — it’s going to cause challenges for water quality, there’s no doubt about it,” the expert said.

The City Island cluster performed better than the others because of its proximity to less developed areas and to longtime efforts by locals to keep the shores clean, Linderoth added.

While the Big Apple performed slightly crappier in 2025, the Long Island Sound overall saw a positive swing.

Across the region, 77% of the 192 Long Island Sound beaches that were sampled at least nine times during the 2025 swimming season received A or B grades — the highest percentage since 2022 and a 5% improvement from 2024.

“The westernmost portion just remains challenged, which makes sense. And it just remains an area that still needs additional and extensive attention to get to the water quality that we want to see,” Linderoth said.

Ultimately, the only way to properly address the bacterial challenges is to expand green infrastructure like rain gardens, bioswales, green roofs and constructed wetlands that could filter the polluted water before it reaches the Long Island Sound.