It's summer, and people around the U.S. are worried about getting their bodies into beach-ready shape. But is the water at your local beach a threat to your health? A new report from the Natural Resources Defense Council (NRDC) offers answers, as well as tips to help you find the healthiest beaches in your area.

The NRDC's 21st annual beachwater quality report, released on Wednesday, covers 200 of America's most popular beaches and reports on the effects of stormwater runoff, sewage overflows, human and animal waste and oil on water quality. According to the NRDC, last year witnessed the second-highest number of beach closings and advisory days in the last two decades.
"America's beaches have long suffered from pollution — the difference is now we know what to do about it," said NRDC senior attorney Jon Devine in a prepared statement. "By making our communities literally greener on land, we can make the water at the beach cleaner. In the years to come, there's no reason we can't reverse this dirty legacy."
"Clean beachwater is not only good for public health, it supports healthy coastal economies that generate billions of dollars and support millions of American jobs," said David Beckman, NRDC's director of the water program. "By taking steps to stop the biggest sources of pollution in the waves, we can help keep trips to beach carefree, and support our lucrative tourism industries nationwide."
NRDC ranks beaches on a five-star system. According to the organization, "stars are earned for exceeding health standards less than 5 percent of the time last year and over the last three years, and for the following best practices: testing more than once a week, notifying the public promptly when tests reveal bacteria levels exceeding health standards, and posting closings and advisories both online and at the beach."
This year's report identifies 10 "repeat offender" beaches that had consistent water contamination problems from 2006 to 2010. They include three sections of Avalon Beach, two sections of Doheny State Beach (pictured below), and Cabrillo Beach Station in California.; Keaton Beach in Florida; North Point Marina in Illinois; Beachwood Beach West in New Jersey; Villa Angela State Park in Ohio; Ropes Park in Texas; and Eichelman and South Shore beaches in Wisconsin.

Water contamination at each of these beaches exceeded public health standards more than 25 percent of the time in each of the last five years.
NRDC has also, for the first time, identified four "superstar" beaches, which received five-star ratings and have had perfect water-testing results for the past three years. They include Rehoboth Avenue Beach and Dewey Beach in Delaware; Park Point Lafayette Community Club Beach in Minnesota; and Hampton Beach State Park in New Hampshire.
If your beach is not on NRDC's list, the report also offers several tips on finding the healthiest beach in your area, including asking local or state health departments what pollution might be present in the waters where you wish to swim and what water quality monitoring procedures they have in place. The report also suggests avoiding water that is cloudy or smells bad, not swimming 24 hours after a heavy rain, and keeping your head out of the water.
Check out the full report on the NRDC website. 
Inset photo of Doheny State Beach: ChazWags/Flickr
America's dirtiest beaches revealed
New NRDC report showcases the country's unhealthiest beaches, as well as four of its best.