It's summertime. That means vacation time.

And that's why I paid attention recently when a group called Environment America came out with a report on 2,620 U.S. beaches, and how often each one tested positive for potentially unsafe water.

Let's not mince words. By "unsafe water" we mean (sorry, this is gross), "potentially unsafe levels of fecal contamination."

Causes include "urban runoff, sewage leaks and overflows, and industrial-scale livestock operations," according to the report.

I don't want to ruin your vacation, but just in case your plans involve travel to any of the rather unsavory spots on the list, here are the 10 worst beaches in America as judged by the report.

Their places on the list are based on the percentage of days that water tested positive -- meaning they revealed potential contaminants.

1.    Singing Bridge Beach (Arenac County, Michigan)

The water at this beach was tested 11 times. All 11 times, it came up with potentially unsafe water. I've never been there, but you couldn't pay me enough to go in this water if I were to visit. 

2.    San Pedro Creek    (San Mateo County, California)

There were 47 tests here; 43 of them came up positive. That works out to 91 percent.

3.     Cole Park    (Nueces County, Texas)

There were three test sites on the Environment America list. The first was tested 64 times and came up positive 52 times (81 percent). The second was tested 53 times and came up positive 42 times (79 percent), and the third one was tested 56 times and came up positive 38 times (68 percent).

4.    Maumee Bay State Park (Inland)    (Lucas County, Ohio)

This is a state park in Ohio on Maumee Bay, on the western edge of Lake Erie. It was tested 43 times and came up positive 56 times (77 percent).

5.    Sunset Bay, North Parking Lot Creek    (Coos County, Oregon)

There was a small sample size here -- only four tests, three of which came up positive, for 75 percent. So we'll include it on the list with a bit of an asterisk. 

6.    Pier Park    (Wayne County, Michigan)

Tests here came up positive 75 percent of the time: 15 out of 20 tests.

7.    Punaluu Beach Park    (Honolulu, Hawaii)

This is disappointing, and a surprise: again, a 75 percent positive testing record, with nine tests coming up positive out of 12. (Note this beach is on Oahu; there's one with a similar name on the Big Island). 

8.    Kings Ferry    (Chatham County, Georgia)

Another small sample size -- just four tests, three of which came up positive, for 75 percent. So like Sunset Bay in Oregon, I'd take this with a grain of salt and double check more current results.

9.    Ropes Park - Site 2    (Nueces County, Texas)

This is in the same county as Beach No. 2, Cole Park. It had 43 positive tests out of 59, for 73 percent.

10.    Harris Beach State Park at Harris Creek    (Curry County, Oregon)

Not far from Sunset Bay Park, above. It also has a fairly small sample size: five out of seven tests came up positive, for 71 percent.

Now, there is some good news on the list, too. Three counties in particular had some of the cleanest water according to the report -- one each in Delaware, Georgia, and New Hampshire:

  • Sussex County, Delaware (5 among the 15 with the best scores, including the only three on the list that never tested positive)
  • Glynn County, Georgia (6 among the 15 with the best scores)
  • Rockingham County, New Hampshire (3)

As mentioned, this is just the start of the list; the Environment America report includes data on roughly 2,600 other beach testing sites besides the ones above. (.pdf link here). So if you're heading to the beach, I suspect you might want to check out the full report first.