(CNN) -- If you're going to the beach this summer, here's some news for you. In its survey "Testing the Waters," the Natural Resources Defense Council says some places do a great job of making sure it's safe to go in the water, while others aren't doing so well.

How safe is your beach? And if there were a problem lurking in the water, would you know it?

The NRDC used its own surveys and government data on beach closings and advisories to see what beach communities across the country are doing to test water quality. It also checked whether authorities are alerting people when they shouldn't go in the water.

Seven popular destinations that keep a close eye on the water earned a place on this year's "beach club" list: Half Moon Bay in California; Rehoboth Beach, Delaware; Indiana Dunes National Lakeshore; Wellfleet, Massachusetts; Cape May, New Jersey; Cape Hatteras, North Carolina; and Myrtle Beach, South Carolina.

Pollution, bacteria and other microorganisms can cause infections, rashes, and other health problems -- exactly what you don't want to worry about on vacation. And without water monitoring, beachgoers usually don't know there's a problem.

The NRDC report criticizes several places that don't test -- and don't tell. On this year's "beach bum" list: Alabama, Georgia, Louisiana, Oregon and Washington state. Eighteen other states and territories do limited monitoring.

The report called for more controls on potential pollutants and uniform monitoring and notification plans.