Water Distribution Exam Study
Guide+Questions and Answers Verified
100% Correct
valves needed at pipe crosses - ANSWER three
valves needed at pipe tees - ANSWER two
min acceptable CL2 residual when using chloramines for disinfection - ANSWER .6 mg/L
CL2 residual needed to disinfect well casings - ANSWER 50 ml/L
backflows are installed downstream from the what - ANSWER meter
double check backflows offer what level of protection - ANSWER least
RP backflows offer what level of protection - ANSWER medium
RP backflows have what between two check valves - ANSWER relief valve
what offers the highest level of backflow protection - ANSWER air gap
min and max distance backflows to be off ground - ANSWER 12 min 30 inches max
what is a more powerful disinfectant than chloramines - ANSWER chlorine
,what disinfectant is more persistent than chlorine - ANSWER chloramines
chloramines are more effective than chlorine against what - ANSWER biofilms
main chlorination at 25-50 mg/L is held for how long - ANSWER 24 hours
min CL2 residual for main after 24 hour hold - ANSWER 10 mg/L
main slug method at 100 mg/l must be held for min of - ANSWER 3 hours
calcium hypochlorite can support a fire when stored close to what - ANSWER organics
if CL2 residual leaving plant falls below .20, how long do you have to correct the
problem - ANSWER 4 hours, if corrected under 4 hours not a violation, but
regulatory agency must be notified
convert F to C - ANSWER (F-32)/1.8
convert C to F - ANSWER (C x 1.8) + 32
how many times a day are CL2 residuals taken at small plants - ANSWER 3 times a day
how often are CL2 residuals taken at large plants - ANSWER every 2 hours
CL2 gas is extremely toxic and corrosive in what kind of atmosphere - ANSWER moist
,respiratory protection must be certified by what - ANSWER niosh national institute for
occupational safety health
when CL2 gas exceeds what level a full face respirator is needed - ANSWER .5 ppm
respiratory protection needed during an uncontrolled release - ANSWER SCBA
how often should reservoirs be inspected - ANSWER weekly
how often should valves be inspected - ANSWER annually
how often should valve boxes be inspected - ANSWER annually
Why should ARV's be inspected after heavy rains or floods - ANSWER
submersion danger
what should you do if you suspect reservoir vandalism - ANSWER shut it down
national secondary drinking water regulations apply to contaminants that effect what -
ANSWER aesthetic quality of drinking water
lead and copper samples are taken from first draw, cold, kitchen or bath at what min
and max times - ANSWER min 6 hours, max 12 hours
What survey collects the following, location, date, name, building rep, water
source, piping system, points of interconnection, special equipment, remarks,
recommendations - ANSWER cross connection survey
, what 2 types of backflows are used at dangerous applications with health
hazard potential - ANSWER air gap or RP
Two places pipe leaks typically originate from - ANSWER weakened joint or
fitting, damaged or corroded portion of the pipe
what is done when no specific reason is found for significant water loss - ANSWER
water control study
pressure surveys are conducted to indicate what - ANSWER hydraulic efficiency
the following is recorded during what activity, date, time location, pressure zone,
main diameter, main length, flush rate gpm, velocity ft/sec, time to clear, description
of appearance and odor - ANSWER hydrant flushing
what are entry and exit points for foam swabs in small water mains - ANSWER
fire hydrants, air valves, blow offs, wyes, tees
recommended speed for main swab cleaning - ANSWER 2 - 4 feet per second
what must be done after cleaning mains with swabs or pigs - ANSWER chlorinate and
flush
why should valves be exercised - ANSWER extend the life, clean encrustations from
valves and seats, verify they work
noisy or vibrating valves may be an indication what is occurring - ANSWER cavitation
Guide+Questions and Answers Verified
100% Correct
valves needed at pipe crosses - ANSWER three
valves needed at pipe tees - ANSWER two
min acceptable CL2 residual when using chloramines for disinfection - ANSWER .6 mg/L
CL2 residual needed to disinfect well casings - ANSWER 50 ml/L
backflows are installed downstream from the what - ANSWER meter
double check backflows offer what level of protection - ANSWER least
RP backflows offer what level of protection - ANSWER medium
RP backflows have what between two check valves - ANSWER relief valve
what offers the highest level of backflow protection - ANSWER air gap
min and max distance backflows to be off ground - ANSWER 12 min 30 inches max
what is a more powerful disinfectant than chloramines - ANSWER chlorine
,what disinfectant is more persistent than chlorine - ANSWER chloramines
chloramines are more effective than chlorine against what - ANSWER biofilms
main chlorination at 25-50 mg/L is held for how long - ANSWER 24 hours
min CL2 residual for main after 24 hour hold - ANSWER 10 mg/L
main slug method at 100 mg/l must be held for min of - ANSWER 3 hours
calcium hypochlorite can support a fire when stored close to what - ANSWER organics
if CL2 residual leaving plant falls below .20, how long do you have to correct the
problem - ANSWER 4 hours, if corrected under 4 hours not a violation, but
regulatory agency must be notified
convert F to C - ANSWER (F-32)/1.8
convert C to F - ANSWER (C x 1.8) + 32
how many times a day are CL2 residuals taken at small plants - ANSWER 3 times a day
how often are CL2 residuals taken at large plants - ANSWER every 2 hours
CL2 gas is extremely toxic and corrosive in what kind of atmosphere - ANSWER moist
,respiratory protection must be certified by what - ANSWER niosh national institute for
occupational safety health
when CL2 gas exceeds what level a full face respirator is needed - ANSWER .5 ppm
respiratory protection needed during an uncontrolled release - ANSWER SCBA
how often should reservoirs be inspected - ANSWER weekly
how often should valves be inspected - ANSWER annually
how often should valve boxes be inspected - ANSWER annually
Why should ARV's be inspected after heavy rains or floods - ANSWER
submersion danger
what should you do if you suspect reservoir vandalism - ANSWER shut it down
national secondary drinking water regulations apply to contaminants that effect what -
ANSWER aesthetic quality of drinking water
lead and copper samples are taken from first draw, cold, kitchen or bath at what min
and max times - ANSWER min 6 hours, max 12 hours
What survey collects the following, location, date, name, building rep, water
source, piping system, points of interconnection, special equipment, remarks,
recommendations - ANSWER cross connection survey
, what 2 types of backflows are used at dangerous applications with health
hazard potential - ANSWER air gap or RP
Two places pipe leaks typically originate from - ANSWER weakened joint or
fitting, damaged or corroded portion of the pipe
what is done when no specific reason is found for significant water loss - ANSWER
water control study
pressure surveys are conducted to indicate what - ANSWER hydraulic efficiency
the following is recorded during what activity, date, time location, pressure zone,
main diameter, main length, flush rate gpm, velocity ft/sec, time to clear, description
of appearance and odor - ANSWER hydrant flushing
what are entry and exit points for foam swabs in small water mains - ANSWER
fire hydrants, air valves, blow offs, wyes, tees
recommended speed for main swab cleaning - ANSWER 2 - 4 feet per second
what must be done after cleaning mains with swabs or pigs - ANSWER chlorinate and
flush
why should valves be exercised - ANSWER extend the life, clean encrustations from
valves and seats, verify they work
noisy or vibrating valves may be an indication what is occurring - ANSWER cavitation
