1. Direct everyone to leave the pool. If multiple pools use the same filter—all pools shall be shut down. Do not allow anyone to enter the contaminated pool(s) until all decontamination procedures are completed.

2. Remove as much of the fecal material, or vomitus as possible using a net or scoop and dispose of it in a sanitary manner. Clean and disinfect the net or scoop. The net or scoop may be disinfected after cleaning it by leaving the net or scoop immersed in the pool water during disinfection. Vacuuming stool from the pool is not recommended.

3. Raise the chlorine to at least 2 ppm (if less than 2 ppm), and ensure the pH is between 7.2 - 7.5. This chlorine concentration was selected to keep the pool closure time to approximately 30 minutes. Other concentrations or closure times can be used as long as the CT inactivation value (Figure 1) is kept constant.

4. Maintain the chlorine concentration at least 2.0 ppm, pH 7.2 - 7.5, for at least 25 minutes before reopening the pool. The Health Officer may require higher chlorine levels in the presence of chlorine stabilizers such as chlorinated isocyanurates. Ensure that the filtration system is operating while the pool reaches and maintains the proper free available chlorine concentration during the disinfection process.

Figure 1. Giardia Inactivation for Formed Fecal Accident

Chlorine Levels (ppm)	Disinfection Time*
1.0	45 minutes
2.0	25 minutes
3.0	19 minutes

* These closure times are based on a 99.9% inactivation of Giardia cysts by chlorine, pH 7.5, 77° F (25° C). The closure times were derived from the Environmental Protection Agency (EPA) Disinfection Profiling and Benchmarking Guidance Manual. These closure times do not take into account “dead spots” and other areas of poor pool water mixing.

For fecal accidents involving diarrhea

1. Direct everyone to leave the pool. If multiple pools use the same filter—all pools shall be shut down. Do not allow anyone to enter the contaminated pool(s) until all decontamination procedures are completed.

2. Remove as much of the fecal material as possible using a net or scoop and dispose of it in a sanitary manner. Clean and disinfect the net or scoop. The net or scoop may be disinfected after cleaning it by leaving the net or scoop immersed in the pool water during disinfection. Vacuuming stool from the pool is not recommended.

3. Raise the free available chlorine concentration to at least 20 ppm and maintain the pH between 7.2 and 7.5. This chlorine and pH level should be sufficient to inactivate Cryptosporidium and should be maintained for at least 8 hours, equivalent to a CT inactivation value of 9600 (Figure 2).

4. Ensure that the filtration system is operating while the pool reaches and maintains the proper chlorine level during disinfection. If necessary, consult an aquatics professional to determine and identify the feasibility, practical methods, and safety considerations before attempting the hyperchlorination of any pool.

5. Backwash the filter thoroughly after reaching the CT value. Be sure the effluent is discharged directly to waste and in accordance with City of Wichita regulations. Do not return the backwash through the filter. Where appropriate, replace the filter media.

6. Swimmers may be allowed back into the pool after the required CT value has been achieved and the chlorine level has been returned to the normal operating range allowed by Section 7.72.120.

Figure 2. Cryptosporidium Inactivation Time for Diarrheal Accident