"It's alarming that a public pool, where you're supposed to keep these things maintained diligently, was allowed to get its levels so low that that much bacteria was starting to grow," Hampy said.
The bottom line: pool number three is dirty, at such a level that it's unhealthy for swimmers. So would our microbial consultant swim in this pool?
"There is no chance at all," Hampy said.
So, what can you do?
If you can't see to the bottom of the pool, it's probably not clean. Stay out of it.
To check further, try chlorine or pH test strips, which cost $10 to $15. You just dip one in and it changes color to tell you if the pool has the right pH and chlorine levels.
On the other hand, if the pool has a strong chemical odor, it may have too much chlorine, which is an irritant.
Do not swallow pool water. It can even make healthy people sick.
And finally, do your part by not using a pool if you're sick or have an open wound and take kids on frequent bathroom breaks.
As for the persistent rumor that some pools put a chemical in the water that will expose people who pee in the water by turning their urine bright red, it's an urban myth. There is no such chemical. The urine of healthy people is typically sterile, so it's not nearly as much of a concern. Not that I'm recommending peeing in the pool!
Nearly 300 children under the age of five drown in residential and public pools each year, according to the Consumer Product Safety Commission's website, Poolsafety.gov. All swimmers should be aware of the potential for drowning.
The CPSC has put together tips to keep your family safe in and around the pool this summer.
There are simple steps that pool owners can take to make your pool a safer space for kids:
Children must be supervised at all times around a pool.
Install four-sided fencing around pools. If your house serves as the fourth side of a fence around a pool, install a pool or door alarm.
Get training in CPR and water rescue skills.
Have life-saving equipment such as life rings or floats nearby.
Make sure pools have safety drain covers.
For pool safety tips, information on swimming lessons and more, visit Poolsafety.gov.