Certified Pool Operator Handbook Practice Test -
questions and answers 2025\2026 A+ Grade
1. You operate a 120,000-gallon pool, and upon performing your hourly chemical tests you observe the
following readings: Total Available Chlorine reading is 1.6 free available chlorine reading is 1.5 pH is 7.4
Your supervising lifeguard has just informed you that you have had a fecal incident occur; a solid stool
has been discharged into the pool. According to the Centers for Disease Control, as the CPO, you should
do the following:
- correct answer clear the pool and raise the free chlorine to 2 ppm
2. Assuming that your local health department requires you to raise the free chlorine to 5 ppm, how
much sodium hypochlorite would be needed to raise the free chlorine in the pool in question #1 to that
level?
- correct answer 3.5 gallons
3. You are the CPO for an indoor health club pool. The facility manager informs you that he is receiving
complaints about a strong chlorine odor in the pool area, and several members have complained of eye
irritation. The most likely cause of these complaints is:
- correct answer high levels of chloramines in the pool
4. To determine the level of chloramines in the water, you should do which of the following?
- correct answer test for total chlorine and free chlorine, then subtract the free chlorine number from
the total chlorine
5. You operate a 45,000 gallon indoor pool, and upon doing your hourly chemical tests you observe the
following readings:Total available chlorine is 2.2 Free available chlorine is 1.4 and pH is 7.6 What is the
level of chloramines in this pool?
- correct answer 0.8
7. You are the operator of a 330,000 gallon outdoor pool. Your local health department requires you to
perform a water balance calculation once monthly. Upon performing the water tests necessary to
perform this calculation, you observe the following readings in your pool: Total alkalinity is 50 ppm pH is
7.2 Calcium Hardness is 150 ppm Temperature is 76 degrees F Total Dissolved Solids is 500 ppm Using
these readings, what is the Saturation Index for this pool?
- correct answer -0.8
, 8. To adjust the tested Total Alkalinity in the pool in question #7 to an acceptable level, which chemical
would be most appropriate?
- correct answer Sodium Bicarbonate
9. To adjust the tested pH in the pool in question #7 to an acceptable level, which chemical would be
most appropriate?
- correct answer Sodium Carbonate
10. You are the CPO for a 28,000 gallon hotel pool. You perform a water balance chemical test, and to
your surprise, the Calcium Hardness is only 100 ppm. How much calcium chloride (77%) would be
required to increase this to 400 ppm?"
- correct answer 100.8 lbs.
11. You are the CPO for a 100 foot long, 50 foot wide country club pool. The average depth of this pool is
7 feet. You return to the pool on Monday morning, after a rare weekend off, and find that the auto-fill
feature has failed to work, and the pool water level is four inches too low. How many gallons of water
must be added to return the water to the proper level?
- correct answer 12,495 gallons
12. You are the operator of a 3,000 gallon health club spa, which has an average of 100 users per day.
According to the CPO Handbook, how often should the water in this spa be changed?
- correct answer 10 days
"13. You are the CPO for a large municipal swimming pool. This pool has a volume of 560,000 gallons of
water,and has an average daily bather load of 1300 people. The pool is operated using high rate
pressure sand filters. How often should you backwash the filters?"
- correct answer When the influent and effluent gauges are 10 to 20 psi apart
14. In testing for Chlorine/Bromine in a commercial pool, DPD is preferred over OTO because:
- correct answer OTO only tests for Total Chlorine
15. Safety and rescue equipment should always be:
- correct answer Kept easily accessible around the pool
questions and answers 2025\2026 A+ Grade
1. You operate a 120,000-gallon pool, and upon performing your hourly chemical tests you observe the
following readings: Total Available Chlorine reading is 1.6 free available chlorine reading is 1.5 pH is 7.4
Your supervising lifeguard has just informed you that you have had a fecal incident occur; a solid stool
has been discharged into the pool. According to the Centers for Disease Control, as the CPO, you should
do the following:
- correct answer clear the pool and raise the free chlorine to 2 ppm
2. Assuming that your local health department requires you to raise the free chlorine to 5 ppm, how
much sodium hypochlorite would be needed to raise the free chlorine in the pool in question #1 to that
level?
- correct answer 3.5 gallons
3. You are the CPO for an indoor health club pool. The facility manager informs you that he is receiving
complaints about a strong chlorine odor in the pool area, and several members have complained of eye
irritation. The most likely cause of these complaints is:
- correct answer high levels of chloramines in the pool
4. To determine the level of chloramines in the water, you should do which of the following?
- correct answer test for total chlorine and free chlorine, then subtract the free chlorine number from
the total chlorine
5. You operate a 45,000 gallon indoor pool, and upon doing your hourly chemical tests you observe the
following readings:Total available chlorine is 2.2 Free available chlorine is 1.4 and pH is 7.6 What is the
level of chloramines in this pool?
- correct answer 0.8
7. You are the operator of a 330,000 gallon outdoor pool. Your local health department requires you to
perform a water balance calculation once monthly. Upon performing the water tests necessary to
perform this calculation, you observe the following readings in your pool: Total alkalinity is 50 ppm pH is
7.2 Calcium Hardness is 150 ppm Temperature is 76 degrees F Total Dissolved Solids is 500 ppm Using
these readings, what is the Saturation Index for this pool?
- correct answer -0.8
, 8. To adjust the tested Total Alkalinity in the pool in question #7 to an acceptable level, which chemical
would be most appropriate?
- correct answer Sodium Bicarbonate
9. To adjust the tested pH in the pool in question #7 to an acceptable level, which chemical would be
most appropriate?
- correct answer Sodium Carbonate
10. You are the CPO for a 28,000 gallon hotel pool. You perform a water balance chemical test, and to
your surprise, the Calcium Hardness is only 100 ppm. How much calcium chloride (77%) would be
required to increase this to 400 ppm?"
- correct answer 100.8 lbs.
11. You are the CPO for a 100 foot long, 50 foot wide country club pool. The average depth of this pool is
7 feet. You return to the pool on Monday morning, after a rare weekend off, and find that the auto-fill
feature has failed to work, and the pool water level is four inches too low. How many gallons of water
must be added to return the water to the proper level?
- correct answer 12,495 gallons
12. You are the operator of a 3,000 gallon health club spa, which has an average of 100 users per day.
According to the CPO Handbook, how often should the water in this spa be changed?
- correct answer 10 days
"13. You are the CPO for a large municipal swimming pool. This pool has a volume of 560,000 gallons of
water,and has an average daily bather load of 1300 people. The pool is operated using high rate
pressure sand filters. How often should you backwash the filters?"
- correct answer When the influent and effluent gauges are 10 to 20 psi apart
14. In testing for Chlorine/Bromine in a commercial pool, DPD is preferred over OTO because:
- correct answer OTO only tests for Total Chlorine
15. Safety and rescue equipment should always be:
- correct answer Kept easily accessible around the pool
