The most common germs spread through recreational water are germs that cause diarrheal illnesses and skin rashes. These are spread by swallowing water contaminated with feces or by skin exposure to contaminated water. Pool water is unlikely to spread illness.
Vomit in Pool Water
Vomiting while swimming appears to be a common event. Often, vomiting is a result of swallowing too much water and, therefore, the vomit is probably not infectious. However, if the full contents of the stomach are vomited, follow the guidance in these Q & As:
Q: What germs are likely to be spread by vomit?
A: Noroviruses (also known as Norwalk-like viruses)
Q: Assuming that norovirus is in the vomit, what should I do?
A: Respond to the vomit accident as you would respond to a formed fecal accident, using CDC's recommendations. The time and chlorine level combinations needed to kill noroviruses and Giardia are similar. Since killing Giardia is the basis of CDC’s formed fecal accident response recommendations, this protocol should be adequate for disinfecting a potentially infectious vomit accident.
Blood in Pool Water
Germs (e.g., Hepatitis B virus or HIV) found in blood are spread when infected blood or certain body fluids get into the body and bloodstream (e.g., by sharing needles and by sexual contact). CDC is not aware of any of these germs being transmitted to swimmers from a blood spill in a pool.
Q: Does chlorine kill the germs in blood?
A: Yes. These germs do not survive long when diluted into properly chlorinated pool water.
Q: Swimmers want something to be done after a blood spill. Should the pool be closed for a short period of time?
A: There is no public health reason to recommend closing the pool after a blood spill. However, some pool staff choose to do so temporarily to satisfy patrons.
Check for existing guidelines from your local or state regulatory agency before use. Healthy Swimming recommendations do not replace existing state or local regulations or guidelines.