OCEAN CITY — Just in time for the peak  summer tourist season, Ocean City and resorts in neighboring Delaware are listed among 13 destinations to earn a perfect 5-Star rating in an annual report released this week on water quality at popular beaches around the country.

According to “Testing the Waters: A Guide to Water Quality at Vacation Beaches,” an independent report released on Wednesday by the Natural Resources Defense Council, water quality at beaches in Ocean City earned a perfect 5-Star rating again in 2012 for at least the third consecutive year. For the 23rd year in a row, the NRDC reviewed data supplied by the Environmental Protection Agency (EPA) to rate water quality at beaches on a variety of standards including acceptable levels of bacteria, frequency of monitoring and numbers of closures and advisories over the course of the year.

In 2012, six designated beach locations in Ocean City were tested twice a week during the summer season for a total of 27 samples taken. At each site and at each location, Ocean City’s beaches exceeded the acceptable state and federal standards zero percent of the time and there were no closures or advisory days. Similarly, three locations on Assateague were tested once a week during 2012 and zero samples exceeded the standards and no closures or advisories were issued.

Also included on the NRDC’s list of the nation’s 13 “Superstar” beaches were the neighboring resorts of Dewey Beach and Rehoboth. It’s important to note nearby Fenwick Island and Bethany Beach also had zero samples exceeding the acceptable standards and issued no closures or advisory days, but were not included on the NRDC’s list of 13 “Superstar” beaches in the report.

While the mid-Atlantic ocean beaches scored well in the annual report, the same cannot be said for many of the beach destinations around the country. According to the report, America’s beaches collectively experienced 20,000 closing and advisory days in 2012 for the third consecutive year because of polluted water or threatened contamination. Over 80 percent of the closings and advisories were issued because testing revealed bacteria levels violated public health standards.

“Sewage and contaminated runoff in the water can spoil a family vacation real fast, turning a day of lounging at the beach into a day at the doctor’s office with a sick child,” said NRDC Senior Attorney Jon Devine. “It’s no surprise that pollution in the waves is bad for business in resort communities.”