Exceedance of microbiological parameters response protocol for public swimming pools and spa pools

If, during verification monitoring, there is an exceedance of the Escherichia coli, Pseudomonas aeruginosa, or heterotrophic colony count guideline values, remediation of the affected pool should be undertaken.

Microbiological guideline values for public swimming pools and spa pools

Parameter	Guideline value
Escherichia coli (E. coli)	0 CFU/100 mL or 0 MPN/100 mL
Pseudomonas aeruginosa (P. aeruginosa)	0 CFU/100 mL or 0 MPN/100 mL
Heterotrophic colony count (HCC)	Less than 100 CFU/mL

When microbiological sampling results exceed guideline values for public swimming pools

Check that disinfectant levels meet the minimum requirements of Schedule 1 of the NSW Health Public Health Regulation 2022.
If the pool does not meet the minimum requirements, immediately close the affected pool and any other pools that are hydraulically connected.
If the filtration system incorporates a coagulation step, ensure the coagulant concentration is correct to enhance the filtration process.
Backwash filter media or replace the filter element as appropriate. Precoat filter media should be replaced.
Ensure the water is balanced.
Hygienically clean, disinfect or dispose of materials, tools, equipment or surfaces that have come into contact with contaminated water.
Record the incident and remedial action taken.
Manually test the swimming pool to ensure compliance with minimum operating requirements.
Re-open the pool.

When microbiological sampling results exceed guideline values for public spa pools

Empty all water from the spa (including balance tanks).
Scrub and rinse all surfaces with tap water.
Spray all surfaces with a chlorine solution of one part bleach to 10 parts water. This dilution factor is based on a bleach product containing 10–12.5% sodium hypochlorite. Apply liberally and leave to soak for 10 minutes.
Rinse with tap water known to have an acceptable water quality.
Refill the spa.
Ensure the disinfectant levels meet the minimum requirements of Schedule 1 of the NSW Health Public Health Regulation 2022.
Backwash filter media or replace the filter element as appropriate. Precoat filter media should be replaced.
Ensure the water is balanced and the concentration of disinfectant is acceptable.
Hygienically clean, disinfect or dispose of materials, tools, equipment, or surfaces that have come into contact with contaminated water.
Record the incident and remedial action taken.
Manually test the swimming pool to ensure compliance with minimum operating requirements.
Re-open the spa.

For more information on risk management of a microbiological parameter exceedance in public swimming pools and spa pools, contact your local Public Health Unit on 1300 066 055 for advice.