Water Treatment Class E Cheat Sheet
Exam Questions and Answers 100% Pass
The minimum distance that a potable water line has to be from a sewer line. -
ANSWER-10 Feet
The minimum distance that a potable water line has to be above a sewer line -
ANSWER-1 Foot
Minimum size coupling for a fire hydrant - ANSWER-6 inches
How small must a system be in order to be able to collect all TC samples on one
day? - ANSWER-4900 or fewer served
How soon must a + TC sample be resampled - ANSWER-Within 24 hours of the
positive result
Where must repeat TC tests be sampled - ANSWER-at the same tap, up and down
at most 5 service connections of the positive result
What must a positive TC sample be checked for? - ANSWER-The presence of FC
or EC
Volume of a TC sample - ANSWER-100 mL
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 1
,What must be done before pulling a distribution sample? - ANSWER-Disinfect the
sample point by torching or chemicals
What is the Population Equivalent? - ANSWER-A means of expressing the
amount of organic material in wastewater. In a domestic wastewater system,
microorganisms use up about 0.2 pound (90 grams) of oxygen per day for each
person using the system (as measured by the standard BOD test). May also be
expressed as flow (100 gallons/person/day or 378 liters/person/day) or suspended
solids (0.2 lb SS/person/day or 90 grams SS/person/day).
How do you calculate the population equivalent? - ANSWER-May be expressed as
flow (100 gallons/person/day or 378 liters/person/day) or suspended solids (0.2
lb SS/person/day or 90 grams SS/person/day). Use 2 variables to find the missing
variable.
Volume of a rectangle - ANSWER-HxWxL
Volume of a cylinder - ANSWER-pi x radius squared x height
how do you fill a line with water? - ANSWER-From the lowest point to the
highest point
what concentration of Cl2 must be used to disinfect a distribution line or tank? -
ANSWER-50 ppm
what is the maximum length of a dead end with a 2 inch line? - ANSWER-1500
feet
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 2
, what is a rotameter and what does it measure? - ANSWER-a rotameter is a glass
enclosure with a ball inside used to measure the flow of gas from a cylinder in PPD
(pounds per day)
what must you do when starting a centrifugal pump? - ANSWER-make sure the
suction side valve is open and that the pump is primed
What is Chlorine dose? - ANSWER-The amount of chlorine added to a water
supply
what is chlorine demand? - ANSWER-the amount of chlorine required to "make
the kill"
What is chlorine residual? - ANSWER-The amount of chlorine left over after the
kill
name the processes of a conventional surface water treatment plant - ANSWER-
Coagulation, flocculation, sedimentation and filtration
What is the purpose of The Safe Drinking Water Act? - ANSWER-to protect the
public from waterborne diseases
Name some waterborne diseases - ANSWER-Hepatitis, Anthrax, Dysentery,
Cholera, typhoid fever, giardiasis, gastroenteritis, meningitis, polio
What is the purpose of a transformer? - ANSWER-Reduce voltage
Define ampere - ANSWER-A measure of current strength
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 3
Exam Questions and Answers 100% Pass
The minimum distance that a potable water line has to be from a sewer line. -
ANSWER-10 Feet
The minimum distance that a potable water line has to be above a sewer line -
ANSWER-1 Foot
Minimum size coupling for a fire hydrant - ANSWER-6 inches
How small must a system be in order to be able to collect all TC samples on one
day? - ANSWER-4900 or fewer served
How soon must a + TC sample be resampled - ANSWER-Within 24 hours of the
positive result
Where must repeat TC tests be sampled - ANSWER-at the same tap, up and down
at most 5 service connections of the positive result
What must a positive TC sample be checked for? - ANSWER-The presence of FC
or EC
Volume of a TC sample - ANSWER-100 mL
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 1
,What must be done before pulling a distribution sample? - ANSWER-Disinfect the
sample point by torching or chemicals
What is the Population Equivalent? - ANSWER-A means of expressing the
amount of organic material in wastewater. In a domestic wastewater system,
microorganisms use up about 0.2 pound (90 grams) of oxygen per day for each
person using the system (as measured by the standard BOD test). May also be
expressed as flow (100 gallons/person/day or 378 liters/person/day) or suspended
solids (0.2 lb SS/person/day or 90 grams SS/person/day).
How do you calculate the population equivalent? - ANSWER-May be expressed as
flow (100 gallons/person/day or 378 liters/person/day) or suspended solids (0.2
lb SS/person/day or 90 grams SS/person/day). Use 2 variables to find the missing
variable.
Volume of a rectangle - ANSWER-HxWxL
Volume of a cylinder - ANSWER-pi x radius squared x height
how do you fill a line with water? - ANSWER-From the lowest point to the
highest point
what concentration of Cl2 must be used to disinfect a distribution line or tank? -
ANSWER-50 ppm
what is the maximum length of a dead end with a 2 inch line? - ANSWER-1500
feet
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 2
, what is a rotameter and what does it measure? - ANSWER-a rotameter is a glass
enclosure with a ball inside used to measure the flow of gas from a cylinder in PPD
(pounds per day)
what must you do when starting a centrifugal pump? - ANSWER-make sure the
suction side valve is open and that the pump is primed
What is Chlorine dose? - ANSWER-The amount of chlorine added to a water
supply
what is chlorine demand? - ANSWER-the amount of chlorine required to "make
the kill"
What is chlorine residual? - ANSWER-The amount of chlorine left over after the
kill
name the processes of a conventional surface water treatment plant - ANSWER-
Coagulation, flocculation, sedimentation and filtration
What is the purpose of The Safe Drinking Water Act? - ANSWER-to protect the
public from waterborne diseases
Name some waterborne diseases - ANSWER-Hepatitis, Anthrax, Dysentery,
Cholera, typhoid fever, giardiasis, gastroenteritis, meningitis, polio
What is the purpose of a transformer? - ANSWER-Reduce voltage
Define ampere - ANSWER-A measure of current strength
©️COPYRIGHT 2025, ALL RIGHTS RESERVED. 3
