A newly released report that graded the water quality of beaches across the United States found that 10 percent of the country's shores are contaminated or polluted.

The annual beach report, conducted by the Natural Resources Defense Council (NRDC), discovered that one in 10 beaches in the coastal and Great Lakes region of the United States did not meet the Environmental Protection Agency's recommended standards for safe swimming.

The report found that many beaches across the country have polluted waters caused by stormwater runoff, overflowing sewage and other forms of bacterial contamination. The study was based on water samples collected last year from nearly 3,500 coastal and Great Lakes beaches. [Sand & Surf: The Best Beaches of 2014]

In addition to these troubling finds, the report identified 35 "superstar" beaches and 17 "repeat offenders." The NRDC singled out the superstar beaches for consistently scoring high with national water quality benchmarks — with samples meeting safety standards 98 percent of the time — over the past five years. The repeat offenders were so-named because sections of these seashores have had persistent pollution problems — with water samples failing to meet safety standards more than 25 percent of the time — over the past five years, according to the NRDC.

Here are the NRDC's "superstar" beaches (organized by state):

Alabama

Gulf Shores Public Beach in Baldwin CountyGulf State Park Pavilion in Baldwin CountyDauphin Island Public BeachCalifornia

Newport Beach in Orange County (one of three monitored sections - Newport Beach - 38th Street)Delaware

Dewey Beach-Swedes in Sussex CountyFlorida

Bowman's Beach in Lee CountyCoquina Beach South in Manatee CountyFort Desoto North Beach in Pinellas CountyGeorgia

Tybee Island North in Chatham CountyHawaii

Hapuna Beach St. Rec. Area in Big Island Po'ipu Beach Park in KauaiWailea Beach Park in MauiMassachusetts

Singing Beach in Essex CountyMaryland

Point Lookout State Park in St Mary's CountyAssateague State Park in Worcester CountyNorth Carolina

Ocean Pier at Main St. and Sunset Blvd. in Brunswick CountyBeach at Cape Hatteras Lighthouse in Dare CountyOcean Pier at Salisbury Street in Wrightsville Beach in New Hanover Ocean Pier at Ocean Blvd. and Crews Ave. in Topsail Beach in Pender County New Hampshire

Hampton Beach State Park in Rockingham CountyWallis Sands Beach at Wallis Rd. in Rockingham CountyWallis Sands State Park in Rockingham CountyNew Jersey

Washington (Margate) in Atlantic County40th St. (Avalon) in Cape May County40th St. (Sea Isle City) in Cape May CountyStone Harbor at 96th St. in Cape May CountyUpper Township at Webster Rd. in Cape May CountyWildwood Crest at Orchid in Cape May CountyBroadway (Pt. Pleasant Beach) in Ocean CountyNew York

Long Beach City in Nassau CountyVirginia

Virginia Beach at 28th St. in Virginia Beach County Virginia Beach at 45th St. in Virginia Beach CountyBack Bay Beach in Virginia Beach CountyVirginia Beach - Little Island Beach North in Virginia Beach CountyWashington

Westhaven State Park, South Jetty in Grays HarborHere are the NRDC's "repeat offenders" (organized by state):

California

Malibu Pier, 50 yards east of the pier, in Los Angeles CountyIndiana

Jeorse Park Beach in Lake County (both monitored sections - Lake Jeorse Park Beach I & Lake Jeorse Park Beach II)Massachusetts

Cockle Cove Creek in Barnstable CountyMaine

Goodies Beach in Knox CountyNew Jersey

Beachwood Beach in Ocean CountyNew York

Main Street Beach in Chautauqua CountyWright Park – East in Chautauqua CountyOntario Beach in Monroe CountyOhio

Lakeshore Park in Ashtabula CountyArcadia Beach in Cuyahoga CountyEuclid State Park in Cuyahoga CountyNoble Beach in Cuyahoga CountySims Beach in Cuyahoga CountyVilla Angela State Park in Cuyahoga CountyEdson Creek in Erie CountyWisconsin

South Shore Beach in Milwaukee CountyFollow Denise Chow on Twitter @denisechow. Follow Live Science @livescience, Facebook & Google+. Original article on Live Science.