Officials are urging families to take precautions in order to stop the spread of cryptosporidium.
County officials would not say which pools were infected but they did say the ones that were have been cleaned.
While setting sail on the San Joaquin Delta, Stockton resident Gary Alexander tries to avoid swallowing any water.
Some people may find themselves avoiding the water all together after San Joaquin County health officials reported the "crypto" cases.
“Crypto, also known as cryptosporidiosium; it’s a very small parasite that infects humans and animals, other animals, and causes diarrhea,” said Dr. Alfaro Garza, public heath officer for San Joaquin County. "Normally, over many years, we’ve had like one a year, approximately.”
Crypto might lurk in lakes, public and private pools and even in the delta.
"This is the sort of thing that’s ubiquitous, it’s everywhere," Dr. Garza said. "And not just in this county, as they say, it’s national.”
Garza said most of the cases they’ve seen are from people who have swam in multiple waterways.
“We have some children and we have older people, so probably the whole gamut,” he said.
Garza also said the news shouldn’t alarm anyone as long as they practice good hygiene, like taking a shower before and after a swim and keeping hands clean before preparing meals.
“After a day in the water, you take a shower," Alexander said. "Just like a day in the ocean, you take a shower.”
Crypto may last up to a month, but even if you’ve had diarrhea and don't know if it was crypto, Dr. Garza says it’s best to stay away from pools for at least two weeks.