Class C Water Operator License Exam Questions and Complete Solutions

Class C Water Operator License Exam Questions and Complete Solutions Ammonia mixed with chlorine gas creates a - Answer: white smoke The most difficult part of a water distribution operator's job. - Answer: furnish a continuous supply Physical connection between a safe and potentially unsafe water source. - Answer: cross connection A distribution system is a - Answer: looped system Dead end mains should be flushed - Answer: every month Excess nitrate causes a condition called - Answer: blue baby syndrome Water hardness is caused by - Answer: calcium and magnesium Sewer mains should be __ft away from water mains. - Answer: 9 Water with a pH less than 7 is considered to be - Answer: acidic Bacti records are kept for ____yrs and chemical records are kept for ___yrs. - Answer: 5, 10 Bacti samples have to be returned to the lab within ___hrs of the collection time. - Answer: 30 Color in the water supply should be less than _____ units. - Answer: 15 Chlorine is ______ times heavier than air. - Answer: 2.5 90% of underground pipe failures are related to improper - Answer: backfill and bedding The spoil bank should be located at least ___ft away from the ditch. - Answer: 2 The following minimum residuals is ______mg/L for free chlorine and ____mg/L for total chlorine. - Answer: .2, .5 Public opinion of the water utility is _______ at a standstill. - Answer: never A bacti sample should be taken every ____ft of pipe. - Answer: 1000 The most common collection point for a bacti sample is the water tap _______. - Answer: outside the house A standpipe is considered ground storage unless it exceeds _____ft above the highest ________. - Answer: 80, service connection ________ protection is the electrochemical method for preventing ________ of metal tanks. - Answer: cathodic, corrosion The _____ is the only cross connection control method approved by _______. - Answer: air gap, tceq _______ on a pipeline depend on the _____ or coefficient of pipe roughness. - Answer: friction loss, c factor __________ occurs whenever there is a ______ in the velocity or direction of water flow. - Answer: water hammer, sudden change The ______ water pressure required by the rules and regulations is ____psi under any and all conditions. - Answer: minimum, 20 100, 150, 200 and 250 are approved classes of _____ _____. - Answer: working pressure ______ is used to anchor pipe bends. - Answer: concrete A general deposit of mineral particles evenly along the inside of the pipe is ________. - Answer: tuberculation Shoring should be used if a ditch is ___ft or deeper. - Answer: 5 A written sample writing plan is required for _______ monitoring. - Answer: coliform Ladders should be placed every ___ft in a ditch. - Answer: 25 An oxygen deficient atmosphere is defined as one which contains _____ than ______ % oxygen. - Answer: less, 19.5 Characteristics of a Centrifugal Pump: as the head _____ the discharge ________. - Answer: increases, decreases The operator should leave a ________ of slack in flexible tubing. - Answer: gooseneck The most common type of water meter is the ____ ____ meter. - Answer: positive displacement Safe withdrawal weight from a 150lb cylinder is ___lbs and 400lbs from a ____ton cylinder. - Answer: 40, 1 The most common valve is the _______. - Answer: gate valve The most commonly used fire hydrants used in distribution systems are the _________. - Answer: dry barrel Hydrants have a _____ point in case the hydrant is struck by a vehicle. - Answer: breakaway Controlling valves regulate pressure flow ____ and flow _______. - Answer: rates, direction Electricity is the preferred power source for most distribution systems because of ______, reliability and relatively low _______. - Answer: availability, cost 5/8 meters need to be tested at least every _____ to _______ yrs. - Answer: 5, 10 When disinfecting a water line, use ____mg/L of chlorine in the main and let stand for ____hrs. - Answer: 50, 24 When pressure testing the water main, the test pressure should be ___times as great as the ________ operating pressure. - Answer: 1.5, normal Distribution systems are usually laid out in ____ and/or circular designs. - Answer: loops Dead ends in a system are usually located on ____ shaped or ____ designs. - Answer: tree, grid An operator may refer to Piezometric elevation, static head, or pressure head as ____ height - Answer: vertical water column The main purpose of the water storage facility is to provide ____ amount of water to average or equalize the ______ demands plus provide ______ pressures to fight fires. - Answer: sufficient, daily, minimum Electrical demand in a wiring system is determined by the amount of ____ consumed. - Answer: watts Baffling inside a storage facility may be needed to prevent "hot spots" and ____ flows. - Answer: straight through A mass of concrete placed at bends and valve structures to prevent pipeline movement is commonly called a _____. - Answer: thrust block What is the main difference between surface water and groundwater contamination? - Answer: groundwater takes longer to recover after contamination A cross-connection is a connection between an _____ and an _______ water supply. - Answer: approved, unapproved According to the CDC, which mechanism or problem has caused more waterborne disease outbreaks in the US than any other reported factor? - Answer: leaking backflows What type of water meter is used when the water flow widely fluctuates? - Answer: compound How can mechanical damage to water meters be avoided? - Answer: place it behind the curb and in a meter box A piston meter is a _____ meter. - Answer: displacement Name one advantage to using centrifugal pumps. - Answer: they are easy to repair When residential water meters become worn, they have the tendency to ____ all flows. - Answer: under register _____% of the earth's surface is ocean. - Answer: 75 Out of all the water on earth, less than _____% of freshwater is immediately available to humans. - Answer: 1 The term associated with water that evaporates from living plants is referred to as _____. - Answer: evapotranspiration _____% of all the water on earth is saltwater. - Answer: 97 Bacti sample bottles are prepared with a chemical called _____ before they are sterilized. - Answer: sodium thiosulfate Killing disease causing organisms in the water is the primary purpose of ____ in water mains. - Answer: disinfection Liquified chlorine gas will expand ____ times its original volume. - Answer: 460 Chlorine gas is ____ times heavier than breathing air. - Answer: 2.5 Chlorine gas is considered to be ____% pure. - Answer: 100 Bleach is approximately _____% pure. - Answer: 5.25 HTH dry powder chlorine is set at ____% purity. - Answer: 65 A commonly used method to test for chlorine residual in water is called the ____ method. - Answer: dpd When chlorine gas is added to water, the pH goes down due to the two _____ that form. - Answer: acids Water with a pH of 7.9 is considered to be ______ or _____. - Answer: basic, alkaline A 5' deep pipe trench requires exit ladders every ____ feet and it needs to have approved ____. - Answer: 25. shoring When turning a centrifugal pump off, "this" must be done to prevent water hammer. - Answer: close the discharge valve When an operator isolates a motor from an operable system for repair, it is vital that he/she follow a _____/_____ procedure. - Answer: lockout/tagout Horsepower is defined as _____ft-lbs per minute or 746 watts. - Answer: 33,000 The rated flow of a water meter, as stated by the manufacturer, is based upon ______ flow. - Answer: continuous What is the minimum setback distance for fire hydrants to avoid large vehicle overhang? - Answer: 2ft What is the primary reason for using dry barrel fire hydrants? - Answer: to keep it from freezing You must coordinate a plan for shutdown of a water storage facility so that the distribution system will still be able to _____ upon and after the shutdown. - Answer: meet the customers demands What are the three main components of a centrifugal pump? - Answer: impeller, case and shaft Condensation, evaporation, percolation, and precipitation are all components of the _______ cycle. - Answer: hydrologic The State requires that _____ _____ be kept in storage for disinfection of new water lines. - Answer: calcium hypochlorite If a major chlorine leak occurs, call the supplier and the _____. - Answer: tceq Powder activated carbon is commonly used to treat ____ and ____ problems in water. - Answer: taste, odor The primary goal of coagulation, sedimentation and filtration is to remove ____. - Answer: turbidity The 2 pathogenic protozoans resistant to chlorination are: __________. - Answer: giardia and cryptosporidium The process of separating floc from water by gravity is called ____. - Answer: sedimentation ______ is the last barrier between the public and giardia or cryptosporidium. - Answer: filtration All public water systems in Texas are required to use _____ as the final disinfectant. - Answer: chlorine Water is stored to meet peak demand and to allow production facilities to operate at _______ rates. - Answer: 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. - Answer: 50, 200, 100, 20 The State recommends a TON (Threshold Odor Number) of less than ____. - Answer: 3 In Texas ___% of water is used for commercial, industrial or agricultural purposes. - Answer: 75 In Texas ag water demands accounts for about ___% of the total water used. - Answer: 57 The federal regulator of drinking water is the ___. - Answer: epa The primary state regulator of water utilities is the ____. - Answer: 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. - Answer: 15, 25, 60 Concentrations of fluoride greater than (>) ___mg.L can cause ____ in teeth over time. - Answer: 2, mottling Low doses of heavy metals, such as lead and copper, can cause damage to the ______ _____ ______ over time. - Answer: central nervous system The action level for lead is ____mg.L, and for copper is ____mg/L. - Answer: 0.015, 1.3 One by-product of chlorinated water is ____________, a suspected carcinogen when consumed in water over a lifetime. - Answer: trihalomethane Chlorine is combined with ______ to form chloramines to prevent the formation of _._._._. in surface water. - Answer: ammonia, thms Supply systems must maintain a minimum water pressure of ___ psi under normal conditions and at least ___psi during emergencies. - Answer: 35, 20 Service tap components usually consist of a tapping saddle, corporation stop, service line tubing, curb stop and a _____. - Answer: meter If a repaired main line must be returned to service quickly, dose it with ____mg/L Chlorine, for ___minutes. - Answer: 500, 30 The 2 primary categories of pumps are: ____ and _____. - Answer: centrifugal, positive displacement The "Texas Hazard Communications Act" is known as the "____ ___ ____ Act." - Answer: right to know _____ all shoring from the top down and _____ from the bottom up. - Answer: install, remove