CDC Volume 5: Self -Test Questions
Why is permeability of the subsurface rock important to the flow of groundwater. - Answer-It
determines how easy or difficult it is for water to move.
Why are materials such as sand and gravel considered to be good aquifers for groundwater? - Answer-
Because of their permeability.
If a well is drilled into a confined aquifer, why is a pump not normally necessary for the water to get to
the surface? - Answer-Because of the natural or artesian pressure that exists in the aquifer.
Why are unconfined aquifers more vulnerable to contamination from surface activities? - Answer-They
only have one layer of impermeable material beneath the saturated zone.
What is the benefit to an Air Force base buying drinking water from an adjacent city? - Answer-The
water typically needs little or no treatment.
Even though much of the undesirable material in groundwater if filtered out during the passage through
underground layers of sand, clay, rock, and gravel, what is a major limiting factor in using groundwater a
source of drinking water? - Answer-Excessive mineral content.
Why is groundwater considered to be more advantageous than surface water as a source of drinking
water? - Answer-Because it is less likely to be contaminated with pathogens, have low turbidity,
,maintain nearly constant temperature, be less affected by droughts, and be more difficult to
contaminate.
River water may be safe one day, but significantly contaminated the next. Why is this? - Answer-
Because of the discharge of pollutants into the water.
Why should the nature of a stream or lake be investigated to ensure its dependability as a water source?
- Answer-The availability of surface water may vary widely with each season of the year.
When are complete studies of a water source or adequacy and dependability necessary? - Answer-If the
water source must supply a large and constant amount of water.
What can cause objectionable taste or odor in drinking water? - Answer-The water probably contains
chemicals, minerals, and organic matter such as algae.
Why must the range of alkalinity in water be controlled? - Answer-To prevent acidic corrosion and the
precipitation of salts that can form scale in boilers and circulating cooling water systems.
Why is it important to have adequate dissolved oxygen levels in drinking water? - Answer-Adequate
levels are necessary to prevent the drinking water from tasting flat.
What effect do chemicals and organisms have in polluted water? - Answer-They cause the water to
exhaust its oxygen.
When might drinking water require additional treatment other than chlorine. - Answer-If there are
areas where it's determined there are chlorine-resistant pathogens.
Why is it important to regularly test for microbial pathogens in the water distribution system? - Answer-
To confirm the effectiveness of the water filtration and disinfection practices.
,How do primary drinking water standards protect public health? - Answer-By limiting contaminant
levels in drinking water.
Why is it important to know which regulatory agency has primacy for drinking water criteria at the base?
- Answer-Because primacy identifies the specific agency that has the primary (main) responsibility for
administering and enforcing the drinking water criteria at your installation.
What base drinking water standard(s) must be complied with for installations outside the continental
United States? - Answer-DOD Final Governing Standards or Environmental Governing Standards.
List four typical areas of concern that a base's Well Head Protection Program should address. - Answer-
(1) runoff from the flight line
(2) all operations within the entomology shop
(3) potential surface discharges from any base industrial operations
(4) golf course maintenance operations
Water system classification by the Environmental Protection Agency (EPA) generally depends on what
two factors? - Answer-The number of people served and whether the system serves the same
customers year-round or only on an occasional basis.
What type of water systems do the National Primary Drinking Water Standards (NPDWSs) apply to? -
Answer-Public Water Systems
What is a public water system (PWS)? - Answer-A system that has at least 15 service connections, or
regularly services an average of at least 25 individuals daily at least 60 days a year.
What is a primacy agency? - Answer-The agency of the state or federal government that has primary
enforcement responsibility in accordance with the Safe Drinking Water Act (SDWA)
, What does water treatment consist of? - Answer-Adding or removing substances from water in order to
produce a desired change in quality.
What is the purpose of disinfecting water? - Answer-To inactivate microorganisms in the water, thereby
preventing them from affecting the human body.
What's the difference between a primary and secondary water disinfectant? - Answer-A primary
disinfectant is used to achieve a desired disinfection level to inactivate microo
What is one of the main concerns with adding disinfectants to drinking water? - Answer-Disinfectants
can react with naturally occurring materials in the water to form byproducts such as Trihalomethanes
(TTHM) which may pose a health risk.
Why is chlorine a preferred method of disinfecting water? - Answer-Unlike many other disinfectants,
chlorine leaves a residual in the water, is easily measured and controlled, and is economical to use.
What are the concerns with adding fluoride to drinking water? - Answer-Because an excessive
consumption of fluoride over a lifetime may lead to increased likelihood of effects on bones in adults,
and young children exposed excessive amounts of fluoride have an increase chance of developing pits
and staining in the teeth.
If a water main had a loss of positive pressure less than 20 psi within the main, what actions are
required? - Answer-The water main must be disinfected and tested for coliform bacteria before being
placed back into service.
After the repair of a water main where the slug chlorination method was used, what steps must be
follow next? - Answer-The water line is flushed with potable water and samples are taken for
bacteriological analysis.
Why is permeability of the subsurface rock important to the flow of groundwater. - Answer-It
determines how easy or difficult it is for water to move.
Why are materials such as sand and gravel considered to be good aquifers for groundwater? - Answer-
Because of their permeability.
If a well is drilled into a confined aquifer, why is a pump not normally necessary for the water to get to
the surface? - Answer-Because of the natural or artesian pressure that exists in the aquifer.
Why are unconfined aquifers more vulnerable to contamination from surface activities? - Answer-They
only have one layer of impermeable material beneath the saturated zone.
What is the benefit to an Air Force base buying drinking water from an adjacent city? - Answer-The
water typically needs little or no treatment.
Even though much of the undesirable material in groundwater if filtered out during the passage through
underground layers of sand, clay, rock, and gravel, what is a major limiting factor in using groundwater a
source of drinking water? - Answer-Excessive mineral content.
Why is groundwater considered to be more advantageous than surface water as a source of drinking
water? - Answer-Because it is less likely to be contaminated with pathogens, have low turbidity,
,maintain nearly constant temperature, be less affected by droughts, and be more difficult to
contaminate.
River water may be safe one day, but significantly contaminated the next. Why is this? - Answer-
Because of the discharge of pollutants into the water.
Why should the nature of a stream or lake be investigated to ensure its dependability as a water source?
- Answer-The availability of surface water may vary widely with each season of the year.
When are complete studies of a water source or adequacy and dependability necessary? - Answer-If the
water source must supply a large and constant amount of water.
What can cause objectionable taste or odor in drinking water? - Answer-The water probably contains
chemicals, minerals, and organic matter such as algae.
Why must the range of alkalinity in water be controlled? - Answer-To prevent acidic corrosion and the
precipitation of salts that can form scale in boilers and circulating cooling water systems.
Why is it important to have adequate dissolved oxygen levels in drinking water? - Answer-Adequate
levels are necessary to prevent the drinking water from tasting flat.
What effect do chemicals and organisms have in polluted water? - Answer-They cause the water to
exhaust its oxygen.
When might drinking water require additional treatment other than chlorine. - Answer-If there are
areas where it's determined there are chlorine-resistant pathogens.
Why is it important to regularly test for microbial pathogens in the water distribution system? - Answer-
To confirm the effectiveness of the water filtration and disinfection practices.
,How do primary drinking water standards protect public health? - Answer-By limiting contaminant
levels in drinking water.
Why is it important to know which regulatory agency has primacy for drinking water criteria at the base?
- Answer-Because primacy identifies the specific agency that has the primary (main) responsibility for
administering and enforcing the drinking water criteria at your installation.
What base drinking water standard(s) must be complied with for installations outside the continental
United States? - Answer-DOD Final Governing Standards or Environmental Governing Standards.
List four typical areas of concern that a base's Well Head Protection Program should address. - Answer-
(1) runoff from the flight line
(2) all operations within the entomology shop
(3) potential surface discharges from any base industrial operations
(4) golf course maintenance operations
Water system classification by the Environmental Protection Agency (EPA) generally depends on what
two factors? - Answer-The number of people served and whether the system serves the same
customers year-round or only on an occasional basis.
What type of water systems do the National Primary Drinking Water Standards (NPDWSs) apply to? -
Answer-Public Water Systems
What is a public water system (PWS)? - Answer-A system that has at least 15 service connections, or
regularly services an average of at least 25 individuals daily at least 60 days a year.
What is a primacy agency? - Answer-The agency of the state or federal government that has primary
enforcement responsibility in accordance with the Safe Drinking Water Act (SDWA)
, What does water treatment consist of? - Answer-Adding or removing substances from water in order to
produce a desired change in quality.
What is the purpose of disinfecting water? - Answer-To inactivate microorganisms in the water, thereby
preventing them from affecting the human body.
What's the difference between a primary and secondary water disinfectant? - Answer-A primary
disinfectant is used to achieve a desired disinfection level to inactivate microo
What is one of the main concerns with adding disinfectants to drinking water? - Answer-Disinfectants
can react with naturally occurring materials in the water to form byproducts such as Trihalomethanes
(TTHM) which may pose a health risk.
Why is chlorine a preferred method of disinfecting water? - Answer-Unlike many other disinfectants,
chlorine leaves a residual in the water, is easily measured and controlled, and is economical to use.
What are the concerns with adding fluoride to drinking water? - Answer-Because an excessive
consumption of fluoride over a lifetime may lead to increased likelihood of effects on bones in adults,
and young children exposed excessive amounts of fluoride have an increase chance of developing pits
and staining in the teeth.
If a water main had a loss of positive pressure less than 20 psi within the main, what actions are
required? - Answer-The water main must be disinfected and tested for coliform bacteria before being
placed back into service.
After the repair of a water main where the slug chlorination method was used, what steps must be
follow next? - Answer-The water line is flushed with potable water and samples are taken for
bacteriological analysis.
