PHOENIX - When it comes to the Arizona summer, few things are more refreshing than a swimming pool. There is hardly anything refreshing, though, about the bacteria growing in some Valley pools.

"Crypto(sporidium) causes watery diarrhea, it last for a couple weeks and there's no specific treatment for it," said Jessica Rigler from the Arizona Department of Health Services.

Maricopa County is still feeling the effects of a 2016 Crypto outbreak. As of June, health officials say 43 cases of Crypto have been reported, which is double the normal amount.

"As long as you have the proper chlorine levels, you are going to be pretty OK, but Crypto is a big problem because it's chlorine-resistant," said the Maricopa County Environmental Services Department's Rachel Shauger.

Shauger inspects pools for the county, which includes testing chlorine levels at public pools and community pools at apartment complexes.

Shauger said there isn't any way to know if the water if affected by looking at it.

"You take that gamble of swimming in a pool that maybe somebody was sick swam in," she said.

The good news is public pools are highly regulated by the county, and chlorine levels are checked multiple times a day. However, officials believe the Crypto outbreak from 2016 started at a public aquatics facility.

Cryptosporidium is the "big one" health officials worry about because it is resistant to chlorine, but if chlorine levels dip below normal, there are a host of other issues swimmers may deal with.

E.coli and hepatitus A are just two bacteria John Summons said he's encountered during his 33 years maintaining pools.

"Anything that's within two miles of your pool is going to be in your pool," Summons says.

The nearly year-round pool season in Phoenix doesn't help a problem officials are working to curb.

The problem doesn't mean you need to be afraid of swimming, but it does make paying attention to your surroundings important. Officials say people swimming in cotton or denim clothes can decrease chlorine levels, making the water more likely for contamination. If the water is cloudy or discolored, that can also be a bad sign.