Every year, Heal the Bay, an environmental nonprofit organization, releases its beach report card, which assigns "A-to-F" letter grades to 700 Pacific Coast beaches from Washington State to Tijuana, Mexico.
The grades are based on the bacteria levels in the ocean and this year, California beaches were impacted by 50% more precipitation than the last 10 years.
"Usually, when we clean things, all the dirty water will come into the drains and be treated in waste water treatment plants," said Alison Wu, a water quality data specialist for Heal the Bay. "When rain cleans up things, they also flush everything clean but all the water just goes through the ocean, through the storm drains, without any treatment. So all the dirty things just come into the ocean."
Santa Monica Pier tied Tijuana, Mexico's Playa Blanca for the top spot on Heal The Bay's Beach Bummer list. Researchers suspect that bird fecal matter is a major contributing factor for Santa Monica's ranking.
However, the city has been making efforts to keep the water clean, such as putting bird netting under the pier.
"We have invested over $200 million in water and waste water infrastructure projects," said Sunny Wang, the water resources manager for Santa Monica. "Over half of that is to capture storm water to protect Santa Monica bay as well as increase our local water supplies."
Because of the significant amounts of rainfall, this year's Honor Roll list was the shortest it has ever been.
One tip for beachgoers: Don't enter the water right after it rains.
"Sometimes, some agencies, they cannot sample because after the rainfall, the river is kind of hard to sample," Wu said. "Generally, the water after the rainfall will have elevated bacterial levels."
So before you head to the beach, you can always check for weekly beach report cards here.