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Disinfection Procedures for a Pool Fouling

The Haldimand-Norfolk Health Unit follows the Centers for Disease Control and Prevention recommendations when dealing with a pool fouled by feces or vomit. Diseases can be transmitted when someone swallows pool water that has been contaminated with fecal matter or vomit. Following proper disinfection procedures is essential to destroy any diseases introduced into the pool water when a fouling occurs.

Formed Stool

Formed stool incidents are less of a risk because the germs are confined in the stool. Immediate removal and taking care not to break apart the fecal matter will reduce the likelihood of contamination.

  • Clear the pool of all bathers immediately
  • If you have multiple pools that use the same filter, close all pools down
  • Keep the filtration system in operation during the disinfection process
  • Remove the fecal matter with a net or scoop and dispose of it in a sanitary manner (do not vacuum the stool out)
  • Disinfect the net or scoop, by leaving in the pool during disinfection or using a 50 ppm chlorine solution. This solution can be prepared according to the following chart depending on the concentration of the chlorine used.
  • Raise the Free Available Chlorine level to greater than 2 ppm and ensure the pH is between 7.2 – 7.5. Check the FAC residual at 3 points in the pool
  • Close the pool for an additional 25 minutes after raising the chlorine level
  • Reduce chlorine to normal operating levels prior to reopening the pool
  • Once the pool is reopened for bathers, document the incident and details in the daily records

Diarrhea

  • Clear the pool of all bathers immediately
  • If you have multiple pools that use the same filter, close all pools down
  • Keep the filtration system in operation during the disinfection process
  • Remove as much of the fecal material as possible with a net or scoop and dispose of it in a sanitary manner (do not vacuum the stool out)
  • Disinfect the net or scoop , by leaving in the pool during disinfection or using a 50 ppm chlorine solution
50 ppm chlorine solution
Chlorine concentration (%) Volume of chlorine Volume of water
5.25 20 ml (4 teaspoons) 20 litres (5.3 gallons)
12 10 ml (2 teaspoons) 20 litres (5.3 gallons)
65 2.5 ml (½ teaspoon) 20 litres (5.3 gallons)
  • Raise the FAC level to 20 ppm, ensure the pH is between 7.2 – 7.5. Maintain the FAC residual for at least 13 hours.
  • Backwash the system at the end of the disinfection process, and replace filter media if necessary (for diatomaceous earth)
  • Reduce chlorine to normal operating levels prior to reopening the pool
  • Once the pool is reopened for bathers, document the incident and details in the daily records

Vomit

Often, vomiting is a result of swallowing too much water and, therefore, the vomit is probably not infectious. However, if the contents of the stomach are vomited, germs such as Noroviruses can be spread. It is important to respond immediately by following the same steps listed above for a formed stool incident.

Blood

Germs from blood are not transmitted to bathers through pool water. There is no public health reason to recommend closing the pool after a blood spill in properly disinfected pool water. An operator may choose to do so to alleviate public fears and should then use the opportunity to check pool chemical levels. Document the incident in the daily records.
For any questions regarding a pool fouling please contact the Haldimand-Norfolk Health Unit at the numbers below.