Distribution Operator Certification Practice Exam

These questions are part of the practice quiz. Start practicing

• What is the primary source of coliforms in a water supply?
• What type of pump is most frequently utilized by public water systems?
• Where are the maximum contaminant levels for water quality indicators specified?
• The goal of the National Primary Drinking Water Regulations is primarily to protect what?
• Fire hydrants should generally be set back from the curb by at least how many feet?
• What information must be included on a tag during a switch lock-out?
• What does OSHA stand for?
• Which of the following best defines the term 'stray-current corrosion'?
• Continued inhalation of radon gas is linked to which health issue?
• What is AWWA's recommended maximum distance between valves in a residential area?
• What is the best angle for a tap on a main?
• What kind of pump incorporates rotating impellers inside a pump case?
• Who is permitted to sign off on a permit required for entry into a confined space?
• Which style of curb box eliminates the possibility of misalignment?
• Which type of valve is considered the best for dampening a water hammer?
• What is the main function of a check valve in a water distribution system?
• What is the main purpose of vacuum breakers in piping connections?
• What is the primary function of a lock-out/tag-out system?
• Which type of valve is commonly used to control flow in water systems?
• Why is it critical to stagger the joints of packing in a stuffing box?
• What is the maximum distance between exits required in trenches 4 ft deep or more?
• What is the primary health risk associated with exposure to trihalomethanes?
• What is the primary purpose of well grouting?
• Which type of direct electronic sensor for level measurement is placed above the water level?
• What should be done to the circuit breaker of electrical equipment being worked on?
• A saddle should be used for?
• Which type of instrumentation should be employed to monitor remote locations effectively?
• Under which condition should push joints not be used?
• Which type of water meter is typically used to measure variable flow rates?
• Which of the following valves can be used to control pressure?
• For best results, what is the minimum flushing velocity when using the unidirectional flushing method?
• Which type of valve is appropriate for supplying water at different pressure zones?
• Which organization is responsible for ensuring workplace safety through standards and regulations?
• What primarily determines the size of water mains, pumping stations, and storage tanks?
• What is the primary source of lead in drinking water?
• Air-relief valves are installed to:
• In what type of fire hydrant design is the main valve located below ground level?
• What is the secondary maximum containment level for copper?
• Which hydrant type features no main valve while having separate valves for each nozzle?
• What is the minimum contact time when using the chlorine tablet method of disinfection?
• What is the potential cross-connection hazard from sprinkler systems?
• Which type of motor is best suited for applications needing quick acceleration with infrequent starts?
• Which service line material is known to cause corrosion when connected to brass valves?
• Which type of violation is considered an acute risk to health?
• What distinguishes primary standards from secondary standards?
• Which agency established the drinking water standards in the US?
• What is the action level for lead in drinking water?
• Contacting utility companies is crucial before repairs to avoid what?
• What is the recommended chlorine dosage when disinfecting a water main using the slug method?
• What type of motor is the simplest of all AC motors, characterized by rotors consisting of a series of bars placed in slots?
• What class of fire involves electrical equipment?
• During water treatment, what does the turbidity level indicate about the water quality?
• What is the term for water samples collected at regular intervals and combined in equal volume with each other?
• What class of fire involves sodium or magnesium?
• Material safety data sheets (MSDS) are required for what?
• Which of the following characteristics of a pump is represented on a pump curve?
• What type of water source typically uses velocity meters for flow measurement?
• Which of the following service line materials is not flexible?
• What class of fire involves oil or grease?
• Which document provides a detailed profile of hazardous substances or mixtures?
• Which of the following types of valve is the best to use to maintain the water level in a tank?
• The secondary standard for manganese recommends that the concentrations not exceed:
• Asbestos-cement pipe contains which of the following materials?
• When present in water, which of the following will increase corrosion rates?
• Which precaution is essential before entering a confined space?
• What is the basis for the number of samples that must be collected for utilities monitoring for lead and copper?
• Which of the following measurements indicates water quality in terms of visibility?
• Current meters are also known as:
• What type of hydrant has no main valve but has a separate valve for each nozzle?
• Which backflow prevention device features a center relief valve?
• What is the name of the pipe that serves as both the inlet and outlet to an elevated tank?
• Which type of temperature sensor uses two wires of different material?
• The primary purpose of hack valves is to prevent:
• Which of the following represents a distribution layout pattern?
• As the temperature of water increases, how does chlorine's disinfecting action change?
• In which type of water main layout are complaints of poor water quality most likely to occur?
• For effective chlorination, what key factor should be monitored?
• Why should operators contact area companies with underground utilities before a repair job?
• Cave-in protection is required for trenches or excavations that are how deep?
• Which type of pipe is typically used in the construction of very large water mains?
• Which of the following devices is used to measure water depths in storage facilities?
• How many hours must the water remain undisturbed in a pipe before collecting a sample for lead and copper analysis?
• Which of the following devices can check water flow in the distribution system?
• When using a power tool to operate a distribution valve, what is the best practice for the final adjustments?
• What best defines the term drawdown?
• Which of the following analytical tests is the most important?
• What is the recommended best time to perform a flushing program on the mains?
• What type of level sensor requires an air supply to operate?
• What is the purpose of a bypass valve on a large size gate valve?
• What is a common indicator of a water main leak?
• Where is the most common location of leaks on old service connections?
• When work is performed in streets, where should the flagman be positioned?
• What is the first step an operator should take when a large main break occurs?
• What parameter is critical in determining the effective pressure in a confined aquifer?
• When is the most effective time to conduct a leak survey?
• What is the main reason for well acidification?
• What should be the priority when establishing a confined space entry plan?
• What type of notification is typically used for urgent public health advisories?
• What is the most common water complaint related to water standards?
• Records on bacteriological analyses should be kept for a minimum of:
• What is the term for corrosion caused by the joining of two different metals?
• What causes turbidity in water?
• Which type of temperature sensor uses semiconductive material?
• Which of the following is a measure of the smoothness of a pipe?
• What is an important consideration when maintaining water distribution systems to prevent water quality issues?
• What is the difference between a weak acid and a strong acid?
• What are common issues caused by improper pressure head in a water system?
• What is the maximum recommended head loss for positive displacement water meters that are less than 2 in.?
• Piping containing reclaimed water should be painted what color?
• AWWA recommends 5/8-in. meters be tested every:
• What is the required public notice timeframe for a monitoring violation?
• How often should the health of workers potentially exposed to hazardous atmospheres be evaluated?
• Which type of piping is most resistant to corrosion?
• Which health efficiency category refers to an organic chemical that is a known carcinogen?
• How is the utility's annual average day demand calculated?
• Which of the following is NOT a typical symbol found on an MSDS?
• Where are chlorine samples typically collected from in the distribution system?
• How is water use for peak hour demand determined?
• Which maintenance practice helps in the prevention of cross-connections in a water distribution system?
• Which type of valve is specifically used in maintaining prime to a pump?
• What is the primary function of a curb box?
• Which of the following parameters is used to indicate the clarity of water?
• What issue can arise from stagnant water in distribution mains?
• Which type of butterfly valve connection is best to use underground?
• Which of the following best defines the cone of depression?
• What should be installed between a fire hydrant and the main?
• An atmosphere is considered oxygen deficient if it contains less than what percentage of oxygen by volume?
• Which of the following metals makes the best anode?
• What does the acronym SCADA stand for?
• Which type of hydrant has no drain mechanism and is under pressure and full of water in the lower barrel?
• Permit-required confined space entry mandates the use of what equipment?
• What is the best method to avoid contamination of a main when installing a new service connection?
• Which of the following is typically a concern with float mechanisms used in water level measurement?
• Which factor determines how many samples must be collected for utilities monitoring lead and copper for the first time?
• What type of rupture or breakage may occur when a pipe is unevenly supported along its length?
• Where should bacteriological samples be collected in the distribution system?
• What water quality problem is most likely to occur at dead-end water mains?
• What type of personal protective equipment should be worn when handling hypochlorites?
• Which pump type is ideally used to increase pressure in large distribution systems?
• Fire demand can account for what percent of total capacity of a storage system?
• What type of ductile-iron pipe joint is primarily used for river crossings and underwater intakes?
• How many inches above the ground surface should the breakaway flange on fire hydrants be located?
• Chlorine neutralization is necessary when a treated water sample is to be analyzed for what purpose?
• Interior copper tubing is usually joined by:
• Fuel oils, gasoline, and other organic compounds may permeate which type of piping?
• What chemical is present in a bacteria sample bottle for the purpose of neutralizing chlorine?
• What is defined as the distance from a well that the cone of depression affects the normal water level?
• What style of curb box fits loosely over the curb box and curb stop?
• What is pressure head caused by?
• What is the recommended contact time when disinfecting water mains with the chlorine slug method?
• An arterial-loop distribution system provides flow from how many directions?
• What is the typical response time for repairing major leaks in a water distribution system?
• What type of software is suggested for maintaining records of turbidity levels?
• Which parameter is typically monitored to manage water quality during distribution?
• After a new water main is installed and pressure tested, it should be:
• Which of the following is most likely a cause of decreasing drawdown and an unchanging static water level?
• Which component in a centrifugal pump is primarily responsible for moving fluid?
• Fire protection facilities for each community are evaluated by which organization?
• What is the residual drawdown of a well defined as?
• Which process is essential for reducing trihalomethane levels in water treatment?
• What does pH measure in a solution?
• What type of level sensor has a pressure transducer connected to contained air via a tube?
• What does turbidity specifically measure in water?
• In the context of fire classes, which of the following materials would be considered when identifying a Class D fire?
• What type of concrete tank is made like a home basement but with more reinforcement?
• In general, how much wider should a trench be than the diameter of the pipe?
• Which condition is least likely to increase soil corrosiveness?
• Why is excessive water pressure to residential homes considered objectionable?
• What is the general maximum practical lift of pumps used in water distribution systems?
• How often should fire hydrants typically be tested for functionality?
• What action must be taken if a public water system fails to meet monitoring requirements?
• Why is it essential to ventilate a valve vault before entry?
• What type of meter is based on the Doppler effect?
• What is the maximum allowable concentration of chlorine in drinking water?
• Records of turbidity analyses must be maintained for at least how long?
• Which gas can cause lung and skin irritation depending on its concentration and exposure time?
• What type of hydrant is typically used for water distribution in areas with freezing temperatures?
• Which of the following is colorless, odorless, lighter than air, highly flammable, and sometimes called swamp gas?
• What concentration of iron is recommended by the secondary standard not to exceed?
• What is the primary advantage of using unidirectional flushing methods?
• How much space should there be between the shoring and the sides of the excavation?
• An example of a large-flow water meter is:
• What should a supervisor do if an employee is performing work in an unsafe manner?
• How often does AWWA recommend that 5/8-in. meters be tested?
• What is the recommended chlorine dosage when disinfecting a water main using the tablet method?
• Which type of water meter is most commonly used for residential applications?
• Which of the following is a requirement for all trenches over 5 ft deep?
• Why should isolation valves be installed at frequent intervals in distribution piping?
• What is defined as a public water system under the SDWA?
• What is a key characteristic of Class A fires?
• What health risk is associated with nitrate in water?
• How must water systems serving a population over 10,000 distribute the consumer confidence report to customers?
• What is the quantity of oxygen that can remain dissolved in water related to?
• What is the main purpose of conducting a leak survey in water distribution systems?
• What must be documented when there is a health-related violation in a water system?
• Which pipe fitting is most commonly used with ductile iron pipe for changes in direction?
• As a general rule, what is the minimum horizontal distance water pipes should be separated from sewer pipes?
• Which of the following mandates the language and methods for public notification?
• What type of level sensor cannot be used when the water body freezes?
• What is the reinforcement method used in prestressed pipe?
• What is one of the primary roles of water system operators?
• What type of meter is primarily used for measuring dirty or corrosive water?
• What is the general purpose of monitoring lead and copper levels in water systems?
• What is the chlorine residual typically used to disinfect large full storage tanks?
• What is the optimal maximum water velocity through pipes under normal operating conditions?
• Which of the following is associated with using a pressure tap to make connections of new mains to an existing main?
• What mechanism in hydrants prevents backflow of water into the main supply?
• Which of the following best defines the term static water level?
• Dry-barrel fire hydrants are typically used in what type of environment?
• How many valves should be installed on main intersections?
• When should packing in a stuffing box be replaced?
• What is the term for the height to which a column of water will rise in a well?
• Which of the following is a measure of a material's opposition to the flow of electric current?
• Which type of hydrant is typically concealed from public view?
• If only two rings of packing are used in the stuffing box, how many degrees should the joints be staggered?
• What is the maximum theoretical suction lift of a centrifugal pump at sea level?
• How long should a new tank be disinfected before a water sample is collected for coliform analysis?
• What type of cleaning plug is made with hardened steel or silicon carbide wire brushes?
• What may result from a main break in the distribution system?
• What is a common application of a bypass valve?
• How are gate valves primarily operated?
• The National Primary Drinking Water Regulations focus on contaminants affecting what?
• What type of meter determines the total flow by multiplying the flow through the meter by a factor?
• What is the recommended minimum water pressure in a distribution system during fire flow conditions?
• What type of concrete reservoir is constructed much like a swimming pool, is rather shallow, and difficult to cover?
• What is a characteristic of a piezometric surface?
• Which of the following types of instruments responds to and displays information?
• Customers usually notice turbidity readings in excess of how many nephelometric turbidity units?
• In managing fire hydrants, what is a primary concern in freezing climates?
• During a confined space entry, how often must the atmosphere be monitored for hazardous conditions?
• What is the minimum diameter of a water main to be used for the installation of a fire hydrant?
• Which factor is most critical when evaluating an excavation area for hazards?
• What is the purpose of a foot valve in a pumping system?
• In which situation is it essential to wear eye goggles?
• What type of pipe can PVC use for tees, elbows, and other fittings?
• Which type of ductile-iron pipe joint is known for being quickly assembled and the least expensive?
• If a confined aquifer's recharge area is elevated, what can be said about the water in the aquifer?
• What is the term for a framework of wood or metal installed to prevent caving of trench walls?
• Which of the following is typically associated with trihalomethanes?
• How should a supervisor handle a problem with an operator?