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CLASS C WATER OPERATOR LICENSE EXAM
QUESTIONS AND ANSWERS UPDATED
(202 5 /202 6 ) (VERIFIED ANSWERS)
100, 150, 200 and 250 are approved classes of _____ _____. - ANS ✓working pressure ______ is used to anchor pipe bends. - ANS ✓concrete A general deposit of mineral particles evenly along the inside of the pipe is ________. - ANS ✓tuberculation Shoring should be used if a ditch is ___ft or deeper. - ANS ✓ 5 A written sample writing plan is required for _______ monitoring. - ANS ✓coliform Ladders should be placed every ___ft in a ditch. - ANS ✓ 25 An oxygen deficient atmosphere is defined as one which contains _____ than ______ % oxygen. - ANS ✓less, 19. Characteristics of a Centrifugal Pump: as the head _____ the discharge ________. - ANS ✓increases, decreases
The operator should leave a ________ of slack in flexible tubing. - ANS ✓gooseneck The most common type of water meter is the ____ ____ meter. - ANS ✓positive displacement Safe withdrawal weight from a 150lb cylinder is ___lbs and 400lbs from a ____ton cylinder. - ANS ✓40, 1 The most common valve is the _______. - ANS ✓gate valve The most commonly used fire hydrants used in distribution systems are the _________. - ANS ✓dry barrel Hydrants have a _____ point in case the hydrant is struck by a vehicle. - ANS ✓breakaway Controlling valves regulate pressure flow ____ and flow _______. - ANS ✓rates, direction Electricity is the preferred power source for most distribution systems because of ______, reliability and relatively low _______. - ANS ✓availability, cost 5/8 meters need to be tested at least every _____ to _______ yrs. - ANS ✓5, 10 When disinfecting a water line, use ____mg/L of chlorine in the main and let stand for ____hrs. - ANS ✓50, 24 When pressure testing the water main, the test pressure should be ___times as great as the ________ operating pressure. - ANS ✓1.5, normal
According to the CDC, which mechanism or problem has caused more waterborne disease outbreaks in the US than any other reported factor? - ANS ✓leaking backflows What type of water meter is used when the water flow widely fluctuates? - ANS ✓compound How can mechanical damage to water meters be avoided? - ANS ✓place it behind the curb and in a meter box A piston meter is a _____ meter. - ANS ✓displacement Name one advantage to using centrifugal pumps. - ANS ✓they are easy to repair When residential water meters become worn, they have the tendency to ____ all flows. - ANS ✓under register _____% of the earth's surface is ocean. - ANS ✓ 75 Out of all the water on earth, less than _____% of freshwater is immediately available to humans. - ANS ✓ 1 The term associated with water that evaporates from living plants is referred to as _____. - ANS ✓evapotranspiration _____% of all the water on earth is saltwater. - ANS ✓ 97 Bacti sample bottles are prepared with a chemical called _____ before they are sterilized. - ANS ✓sodium thiosulfate
Killing disease causing organisms in the water is the primary purpose of ____ in water mains. - ANS ✓disinfection Liquified chlorine gas will expand ____ times its original volume. - ANS ✓ 460 Chlorine gas is ____ times heavier than breathing air. - ANS ✓2. Chlorine gas is considered to be ____% pure. - ANS ✓ 100 Bleach is approximately _____% pure. - ANS ✓5. HTH dry powder chlorine is set at ____% purity. - ANS ✓ 65 A commonly used method to test for chlorine residual in water is called the ____ method. - ANS ✓dpd When chlorine gas is added to water, the pH goes down due to the two _____ that form. - ANS ✓acids Water with a pH of 7.9 is considered to be ______ or _____. - ANS ✓basic, alkaline A 5' deep pipe trench requires exit ladders every ____ feet and it needs to have approved ____. - ANS ✓25. shoring When turning a centrifugal pump off, "this" must be done to prevent water hammer. - ANS ✓close the discharge valve
The primary goal of coagulation, sedimentation and filtration is to remove ____. - ANS ✓turbidity The 2 pathogenic protozoans resistant to chlorination are: __________. - ANS ✓giardia and cryptosporidium The process of separating floc from water by gravity is called ____. - ANS ✓sedimentation ______ is the last barrier between the public and giardia or cryptosporidium.
- ANS ✓filtration All public water systems in Texas are required to use _____ as the final disinfectant. - ANS ✓chlorine Water is stored to meet peak demand and to allow production facilities to operate at _______ rates. - ANS ✓uniform Ground water supply systems serving more than ___ connections must have a total ground storage capacity of ___ gal/connection and elevated storage capacity of ___ gal/connection or pressure tank capacity of __ gal/connection. - ANS ✓50, 200, 100, 20 The State recommends a TON (Threshold Odor Number) of less than ____. - ANS ✓ 3 In Texas ___% of water is used for commercial, industrial or agricultural purposes. - ANS ✓ 75
In Texas ag water demands accounts for about ___% of the total water used.
- ANS ✓ 57 The federal regulator of drinking water is the ___. - ANS ✓epa The primary state regulator of water utilities is the ____. - ANS ✓tceq To be classified as a pws, the system must have at least __ service connections or serve at least __ individuals at least ___ days out of the year. - ANS ✓15, 25, 60 Concentrations of fluoride greater than (>) _mg.L can cause ____ in teeth over time. - ANS ✓2, mottling Low doses of heavy metals, such as lead and copper, can cause damage to the ______ _____ ______ over time. - ANS ✓central nervous system The action level for lead is ____mg.L, and for copper is ____mg/L. - ANS ✓0.015, 1. One by-product of chlorinated water is ____________, a suspected carcinogen when consumed in water over a lifetime. - ANS ✓trihalomethane Chlorine is combined with ______ to form chloramines to prevent the formation of .... in surface water. - ANS ✓ammonia, thms Supply systems must maintain a minimum water pressure of ___ psi under normal conditions and at least ___psi during emergencies. - ANS ✓35, 20 Service tap components usually consist of a tapping saddle, corporation stop, service line tubing, curb stop and a _____. - ANS ✓meter
Sewer mains should be __ft away from water mains. - ANS ✓ 9 Water with a pH less than 7 is considered to be - ANS ✓acidic Bacti records are kept for ____yrs and chemical records are kept for ___yrs. - ANS ✓5, 10 Bacti samples have to be returned to the lab within ___hrs of the collection time. - ANS ✓ 30 Color in the water supply should be less than _____ units. - ANS ✓ 15 Chlorine is ______ times heavier than air. - ANS ✓2. 90% of underground pipe failures are related to improper - ANS ✓backfill and bedding The spoil bank should be located at least ___ft away from the ditch. - ANS ✓ 2 The following minimum residuals is ______mg/L for free chlorine and ____mg/L for total chlorine. - ANS ✓.2,. Public opinion of the water utility is _______ at a standstill. - ANS ✓never A bacti sample should be taken every ____ft of pipe. - ANS ✓ 1000 The most common collection point for a bacti sample is the water tap _______.
A standpipe is considered ground storage unless it exceeds _____ft above the highest ________. - ANS ✓80, service connection ________ protection is the electrochemical method for preventing ________ of metal tanks. - ANS ✓cathodic, corrosion The _____ is the only cross connection control method approved by _______. - ANS ✓air gap, tceq _______ on a pipeline depend on the _____ or coefficient of pipe roughness. - ANS ✓friction loss, c factor __________ occurs whenever there is a ______ in the velocity or direction of water flow. - ANS ✓water hammer, sudden change The ______ water pressure required by the rules and regulations is ____psi under any and all conditions. - ANS ✓minimum, 20
