Water Distribution Exam Sample Text Questions and Answers, Exams of Water Resources Planning and Management

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Water Distribution Exam Sample Text

Questions and Answers

What is the federal law that protects public water supplies from harmful contaminants? - ANSWER-SDWA Safe Drinking Water Act MCL stands for - ANSWER-Maximum Contaminant Level True or False? Primary regulations are mandatory - ANSWER-TRUE Secondary regulations are about what 3 things? - ANSWER-Taste Odor Color of water True or False? Secondary regulations are mandatory - ANSWER-FALSE What is the minimum pressure that must be maintained at all times in a distribution system? - ANSWER-20 PSI The limit for velocity in a system is? - ANSWER-5 ft/sec The spoil pile should be located how far back from the trench wall? - ANSWER-2 feet (min) True or False? A vent in a chlorine room should be located near the ceiling. - ANSWER-FALSE An area is considered unsafe when the oxygen level drops to below a) 19.5% b) 20.2% c) 10.5% d) 19.25% - ANSWER-a) 19.5% The most common valve used in a distribution system is a) butterfly

b) gate c) ball d) check - ANSWER-b) gate A chain of custody is required for a sample a) from collection to disposal b) from collection to the lab c) from the lab to disposal d) all of the above - ANSWER-b) from the collection to the lab 1 (one) cubic foot of water is _____ lbs a) 7. b) 8. c) 27 d) 62.38 - ANSWER-d) 62. How should a CL2 (chlorine) storage room be vented? a) mechanically at the floor b) mechanically at the ceiling c) in the middle of the wall d) no ventilation is required - ANSWER-a) mechanically at the floor If a chlorine leak develops in a room where you are working, you should a) quickly leave the room b) crawl on the floor and quickly leave the room c) close your mouth, hold your head as high as possible and quickly leave the room d) call 911, then leave the room - ANSWER-c) close your mouth, hold your head as high as possible and quickly leave the room a beard could prevent proper use of what safety equipment? a) goggles b) fire extinguisher c) SCBA d) Safety Vest - ANSWER-SCBA (self contained breathing apparatus) Prior to entering a storage tank you should a) Throw a match in the tank to check for explosive gas b) mechanically blow air into the tank c) Do nothing, just go ahead and enter the tank

d) notify your supervisor then carefully proceed - ANSWER-b) mechanically blow air into the tank. When using a fire hydrant, it should be a) fully open b) half way closed c) closed - ANSWER-a) fully open As defined by the regulatory agency or rule, free chlorine (CL2) is a) the amount of chlorine left after the demand is met b) the sum of the demand and the residual c) the amount of chlorine in the entire distribution system - ANSWER-a) the amount of chlorine left after the demand is met A water tap should be installed on the main at this angle - ANSWER-45 degrees What type of valve would be used to control the level in an elevated storage tank? a) gate valve b) ball valve c) altitude valve d) check valve - ANSWER-c) altitude valve What type of sample do you use when you need to find the pH? a) composite 24 hour sample b) composite 8 hour sample c) grab sample d) any of the above - ANSWER-c) grab sample When should a pH sample be taken? a) within 2 days b) within 2 hours c) immediately d) there is no time limit - ANSWER-c) immediately When fecal bottles are received from a certified lab, how do you prepare them for the field? a) wash them out with alcohol b) rinse them with hot water c) do nothing, they come ready to use - ANSWER-c) do nothing, they come ready to use

What types of sample do you use when testing chlorine? a) grab sample b) composite sample c) 24 hour test sample d) none of the above - ANSWER-a) grab sample You have 1 million gallon tank and a 100,000 gallon tank side by side. They are both filled to the same elevation. What would be the pressure difference at the bottom of these tanks? a) 10% higher b) 50% higher c) depends on the elevation d) none, they are the same - ANSWER-d) none, they are the same What device is used to support both ends of a pipe where a meter is to be installed? a) yoke b) saddle c) restraining clamp d) none of the above - ANSWER-a) yoke What is the average pH range for ground or surface water? a) 4- b) 6- c) 8-10 - ANSWER-b) 6- How would you protect a water main from contamination during an installation? a) use protective clothing before entering the ditch b) plug the ends of the main c) plan on working only in good weather d) do nothing - ANSWER-b) plug the ends of the main Cathodes are used in a storage tank to help with what? a) disinfection b) Cleaning the tank c) corrosion control d) grounding the tank - ANSWER-c) corrosion control What represents a measure or electrical current?

a) amps b) volts c) watts d) ohms - ANSWER-a) amps Lead in a distribution system is a) always dangerous to children and pregnant women b) of no concern in water distribution c) only dangerous at a pH of 8.0 - ANSWER-a) always dangerous to children and pregnant women What type of flow meters is most common for residential water taps? a) positive displacement meters b) multiple meters c) venturi meters d) none of the above - ANSWER-a) positive displacement meters A pipe that is described as light weight, easy to install, and corrosion resistant is a) concrete b) asbestos cement c) ductile iron - ANSWER-b) asbestos cement A sample is taken from a single location in the distribution system and comes back clear. This would indicate that a) the distribution system is functioning as desired b) no more samples are required for 7 days c) the tap that was sampled was clear at the exact time and date that the sample was pulled from the tap - ANSWER-c) the tap that was sampled was clear at the exact time and date that the sample was pulled from the tap A customer on a looped system is complaining of stale water. What would you check for? a) coliform b) a closed valve on the distribution system c) is their meter working properly? - ANSWER-b) a closed valve on the distribution system What type of pipe should be installed on a chlorinator? a) PVC b) ductile iron

c) copper - ANSWER-a) PVC How can an operator check for leaks in a chlorine line? a) sniff the line b) check with an ammonia soaked rag c) do nothing - ANSWER-b) check with an ammonia soaked rag ??? What disinfecting a line with chlorine tablets, the tablets should be a) along the bottom of the pipe b) along the top of the pipe c) anywhere in the pipe is ok - ANSWER-b) along the top of the pipe You have exceeded the maximum contaminate level (MCL) for coliform. What action needs to be taken? a) notify the public b) do nothing c) none of the above - ANSWER-a) notify the public The minimum vertical distance between water and sewer lines should be? a) 18 inches b) 3 inches c) 3 feet d) there is no limit - ANSWER-a) 18 inches A corporation stop is used to cut off water at the customer service line. This valve is located where? a) on the water main b) on the water meter c) none of the above - ANSWER-a) on the water main When a wet tap is made on a water main, the water is... a) turned off b) drained from the pipe c) still under pressure from the main - ANSWER-c) still under pressure from the main Water distribution system gate valves should be exercised at least once a a) week

b) every 5 years c) year - ANSWER-c) year An area is considered unsafe when the oxygen content drops below a) 22% b) 10% c) 19.5% - ANSWER-c) 19.5% Exits must be provided within 25 feet of all workers in a trench with a minimum depth of a) 5 feet b) 10 feet c) 8 feet - ANSWER-a) 5 feet Before returning a new or repaired water main to service, the line should be flushed at 2.5 feet per second, then tested for a) friction loss b) compaction c) bacterial contamination - ANSWER-c) bacterial contamination Chlorine residuals in the distribution system should be no less than a) 1.6 mg/L b) 0.2 mg/L c) 0.5 mg/L - ANSWER-b) 0.2 mg/L The most common type of valve in the distribution system is a) globe b) stem c) foot d) gate - ANSWER-d) gate The two types of hydrants are a) high and low volume b) red and white c) dry barrel and wet barrel d) in line and end of line - ANSWER-c) dry barrel and wet barrel The main purpose for thrust blocks in a distribution system at bends and valves are a) to fill the ditch line b) to prevent the movement of pipe

c) to increase pressure - ANSWER-b) to prevent the movement of pipe What type of valve is used to control water hammer? a) gate valve b) pressure relief valve c) ball valve d) globe valve - ANSWER-b) pressure relief valve Why should you flush a check valve before testing the operation? a) to equalize the pressure on both sides of the valve b) to clear any trash or debris from the seat c) you don't need to flush it before you operate it - ANSWER-b) to clear any trash or debris from the seat Disease causing bacteria is referred to as a) pathogenic b) infestation c) germs - ANSWER-a) pathogenic What type of valve is typically used to isolate sections of a distribution system? - ANSWER-Gate Valve What is typically installed at the end of a suction line to a centrifugal pump to help maintain the prime on the pump? a) gate valve b) foot valve c) ball valve - ANSWER-b) foot valve When entering a storage tank, air should be forced in the tank when? a) only before entering b) before you enter and while you are in the tank c) before you enter, then only every hour for 15 minutes - ANSWER-b) before you enter and while you are in the tank The purpose of packing on a centrifugal pump is a) to support the shaft b) to lubricate the bearings c) to support the volute d) to control water leakage - ANSWER-d) to control water leakage

What is the purpose of a wet tap? a) it is easier to install b) to prevent contamination of the water main c) to not interrupt service - ANSWER-b) to prevent contamination of the water main A lockout is used for what? a) keeping operators out of the mechanical room b) prevent the use of specific electrical equipment c) to prevent unauthorized personnel from entering storage facilities - ANSWER-b) prevent the use of specific electrical equipment The main purpose of disinfection of water is to a) kill all organisms b) kill pathogens c) improve the taste and clarity of water - ANSWER-b) kill pathogens A cross connection is a) a type of thrust block b) a cross shaped fitting between two pipes c) a connection between a non-potable and potable water supply - ANSWER-c) a connection between a non-potable and potable water supply What causes water hammer to occur? a) hot water in cold pipes b) air in the lines c) valves being opened or closed too quickly - ANSWER-c) valves being opened or closed too quickly The most important duty of a water distribution operator is a) to deliver safe drinking water b) repair lines as needed c) to keep pressure up for fire protection - ANSWER-a) to deliver safe drinking water Turbidity is a measurement of a) pressure b) dissolved solids c) cloudiness of water - ANSWER-c) cloudiness of water Pumps located near higher elevations in a water distribution system are used to

a) boost pressure in mains b) pump water downhill c) provide more water - ANSWER-a) boost pressure in mains A hydro pneumatic water tanks stores water under pressure by the use of a) head blobs b) air c) volume - ANSWER-b) air