Pool Operator Certification
Questions and Answers Updated
2026/2027 Version | Verified
Answers
1. Class A pool - ANSWER ✅ -any pool intended for use by accredited
competitive aquatic events
-can be used for recreational purposes
2. Class B pool - ANSWER ✅ any pool intended for public recreational use
3. Class C pool - ANSWER ✅ -any pool intended for use by apartments,
condominiums, property owners associations, multi-family owned pools, etc.
-includes pools operated solely for lodgings such as hotels/motels
4. Class D pool - ANSWER ✅ any pool operated for special purposes such as
vortex pools, sand bottom pools, splash pools, float tanks and interactive
water attractions
5. Class E pool - ANSWER ✅ any pool used for physical therapy and operated
above 86 degrees F
6. Class F pool - ANSWER ✅ any pool used for wading purposes
,7. what is the response for formed stool? - ANSWER ✅ 1. raise the free
available chlorine level to 2 ppm and ensure the pH is 7.5 or less at 77 deg.
or higher
2. maintain the chlorine concentration for at least 25 min before opening the
pool
3. ensure the filtration system is operating while the pool reaches and
maintains the proper free chlorine concentration
8. what is the response for diarrheal discharge? - ANSWER ✅ 1. raise the free
available chlorine level to 20 ppm
2. maintain the pH of 7.5 or less at 77 deg. or higher
3. maintain the pH and chlorine level for 12.75 hours
4. backwash the filter after full disinfection time
5. return the chlorine level to normal levels
9. Contamination Time (CT) value - ANSWER ✅ -the concentration of free
chlorine in ppm times time in min
10.what is the CT value for giardia? - ANSWER ✅ 45
11.what is the CT value for crypto - ANSWER ✅ 15,300
12.hypochlorous acid (HCl) - ANSWER ✅ -inactivates pathogens and alage
-oxidizes
-the active killing form of chlorine in water
13.free chlorine - ANSWER ✅ the active available disinfectant in the water
FC= HoCl + OCl-
, 14.combined chlorine - ANSWER ✅ forms when free chlorine reacts with 2
types of contaminants in the water
15.pathogens - ANSWER ✅ bacteria, fungi, viruses and protozoan parasites
16.available chlorine content (acc) - ANSWER ✅ -comparison of the relative
amount of chlorine released into water for different chlorine disinfectants
-developed using chlorine gas as the standard reference of 100%
17.active chlorine percentage - ANSWER ✅ the percentage by weight of the
technical grade active ingredient in the product
18.how does sodium hypochlorite raise the water's Total Dissolved Solids? -
ANSWER ✅ by adding sodium (Na+) and chloride (Cl-) ions to the water
19.sodium hypochlorite (NaOCl) - ANSWER ✅ -liquid chlorine releasing
disinfectant that is the most common disinfectant used
-active strength: 10-12%
-ACC 10-12%
-pH 9-14
20.calcium hypochlorite is used to - ANSWER ✅ superchlorinate the water
21.calcium hypochlorite - ANSWER ✅ -dry form of chlorine
-class 3 oxidizer
-continuous use may result in high calcium levels
-pH 8.5-11
Questions and Answers Updated
2026/2027 Version | Verified
Answers
1. Class A pool - ANSWER ✅ -any pool intended for use by accredited
competitive aquatic events
-can be used for recreational purposes
2. Class B pool - ANSWER ✅ any pool intended for public recreational use
3. Class C pool - ANSWER ✅ -any pool intended for use by apartments,
condominiums, property owners associations, multi-family owned pools, etc.
-includes pools operated solely for lodgings such as hotels/motels
4. Class D pool - ANSWER ✅ any pool operated for special purposes such as
vortex pools, sand bottom pools, splash pools, float tanks and interactive
water attractions
5. Class E pool - ANSWER ✅ any pool used for physical therapy and operated
above 86 degrees F
6. Class F pool - ANSWER ✅ any pool used for wading purposes
,7. what is the response for formed stool? - ANSWER ✅ 1. raise the free
available chlorine level to 2 ppm and ensure the pH is 7.5 or less at 77 deg.
or higher
2. maintain the chlorine concentration for at least 25 min before opening the
pool
3. ensure the filtration system is operating while the pool reaches and
maintains the proper free chlorine concentration
8. what is the response for diarrheal discharge? - ANSWER ✅ 1. raise the free
available chlorine level to 20 ppm
2. maintain the pH of 7.5 or less at 77 deg. or higher
3. maintain the pH and chlorine level for 12.75 hours
4. backwash the filter after full disinfection time
5. return the chlorine level to normal levels
9. Contamination Time (CT) value - ANSWER ✅ -the concentration of free
chlorine in ppm times time in min
10.what is the CT value for giardia? - ANSWER ✅ 45
11.what is the CT value for crypto - ANSWER ✅ 15,300
12.hypochlorous acid (HCl) - ANSWER ✅ -inactivates pathogens and alage
-oxidizes
-the active killing form of chlorine in water
13.free chlorine - ANSWER ✅ the active available disinfectant in the water
FC= HoCl + OCl-
, 14.combined chlorine - ANSWER ✅ forms when free chlorine reacts with 2
types of contaminants in the water
15.pathogens - ANSWER ✅ bacteria, fungi, viruses and protozoan parasites
16.available chlorine content (acc) - ANSWER ✅ -comparison of the relative
amount of chlorine released into water for different chlorine disinfectants
-developed using chlorine gas as the standard reference of 100%
17.active chlorine percentage - ANSWER ✅ the percentage by weight of the
technical grade active ingredient in the product
18.how does sodium hypochlorite raise the water's Total Dissolved Solids? -
ANSWER ✅ by adding sodium (Na+) and chloride (Cl-) ions to the water
19.sodium hypochlorite (NaOCl) - ANSWER ✅ -liquid chlorine releasing
disinfectant that is the most common disinfectant used
-active strength: 10-12%
-ACC 10-12%
-pH 9-14
20.calcium hypochlorite is used to - ANSWER ✅ superchlorinate the water
21.calcium hypochlorite - ANSWER ✅ -dry form of chlorine
-class 3 oxidizer
-continuous use may result in high calcium levels
-pH 8.5-11
