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California Certified Hydrogeologist (CHG) Exam
2026 | Latest Verified Questions and Answers
OVERVIEW DESCRIPTION:
The California Certified Hydrogeologist (CHG) exam is a rigorous, three-hour, computer-based
test administered by the Board for Professional Engineers, Land Surveyors, and Geologists
(BPELSG). Candidates must be licensed Professional Geologists (PGs) with at least five years of
specialized experience to qualify. The exam covers California-specific geology, groundwater
hydraulics, well construction standards, and complex water quality regulations. Mastery of these
topics requires a deep understanding of the state’s unique hydrogeologic conditions, from
alluvial basins to fractured bedrock, and the regulatory framework governing groundwater
management.
What is the primary driving force for groundwater flow according to Darcy's Law?
A) Capillary pressure
B) Hydraulic gradient
C) Atmospheric pressure
D) Vapor pressure
CORRECT ANSWER: B
EXPERT RATIONALE: Hydraulic gradient, defined as the difference in hydraulic head per
unit distance, is the main force driving groundwater flow in aquifers according to
Darcy's Law.
QUESTION 2
Which of the following best describes specific yield?
A) Total water held by the soil matrix
B) Water that drains from saturated material under gravity
C) Water bound to soil particles by molecular attraction
D) The hydraulic head of a saturated zone
CORRECT ANSWER: B
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EXPERT RATIONALE: Specific yield is the volume of water that drains from a saturated
soil or rock due to gravity, expressed as a percentage of the total volume.
QUESTION 3
The zone between the water table and the land surface is called the:
A) Capillary fringe
B) Phreatic zone
C) Vadose zone
D) Saturated zone
CORRECT ANSWER: C
EXPERT RATIONALE: The vadose zone is the unsaturated region above the water table
where pore spaces contain both air and water.
QUESTION 4
Which of the following is a characteristic of a confined aquifer?
A) It receives recharge directly from precipitation above
B) It always has a water table
C) It is bounded above and below by low-permeability layers
D) It is found only in fractured rock formations
CORRECT ANSWER: C
EXPERT RATIONALE: Confined aquifers are overlain and underlain by confining units
(aquitards or aquicludes), which restrict vertical flow into or out of the aquifer.
QUESTION 5
According to the California Water Code Section 13750, what requirement applies to well
construction?
A) Wells must be constructed only by registered geologists
B) Wells must be constructed in a manner that prevents contamination of groundwater
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C) All wells must be at least 500 feet deep
D) Well construction permits are valid for 10 years
CORRECT ANSWER: B
EXPERT RATIONALE: The California Water Code requires that wells be constructed to
prevent pollution or contamination of groundwater, which is the fundamental purpose
of well construction regulations.
QUESTION 6
What does a type curve in the Theis method represent?
A) A permeability trend line from pumping test data
B) A drawdown solution for an ideal confined aquifer
C) An empirical data regression for unconfined aquifers
D) A geochemical plume contour for contaminant transport
CORRECT ANSWER: B
EXPERT RATIONALE: The Theis type curve is a theoretical solution used to match
actual drawdown data to determine aquifer properties in confined aquifers .
QUESTION 7
Which ion is commonly used as a conservative tracer in groundwater studies?
A) Calcium
B) Nitrate
C) Chloride
D) Iron
CORRECT ANSWER: C
EXPERT RATIONALE: Chloride is a conservative ion that does not readily degrade,
adsorb, or participate in reactions in most aquifer systems, making it an ideal tracer .
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QUESTION 8
If a pumping test yields a transmissivity value of 150 m²/day and the saturated
thickness is 15 m, what is the hydraulic conductivity?
A) 0.1 m/day
B) 10 m/day
C) 2250 m/day
D) 1 m/day
CORRECT ANSWER: B
EXPERT RATIONALE: Hydraulic conductivity = Transmissivity / Saturated Thickness =
150 m²/day ÷ 15 m = 10 m/day .
QUESTION 9
Which geologic material typically has the lowest permeability?
A) Sandstone
B) Clay
C) Gravel
D) Fractured limestone
CORRECT ANSWER: B
EXPERT RATIONALE: Clay particles are very small and tightly packed, with tiny pore
spaces that significantly limit water movement, resulting in very low permeability .
QUESTION 10
What process most contributes to saltwater intrusion in coastal aquifers?
A) Natural tidal fluctuations
B) Thermal expansion of ocean water
C) Overpumping of freshwater aquifers
D) Sea level rise only
CORRECT ANSWER: C
California Certified Hydrogeologist (CHG) Exam
2026 | Latest Verified Questions and Answers
OVERVIEW DESCRIPTION:
The California Certified Hydrogeologist (CHG) exam is a rigorous, three-hour, computer-based
test administered by the Board for Professional Engineers, Land Surveyors, and Geologists
(BPELSG). Candidates must be licensed Professional Geologists (PGs) with at least five years of
specialized experience to qualify. The exam covers California-specific geology, groundwater
hydraulics, well construction standards, and complex water quality regulations. Mastery of these
topics requires a deep understanding of the state’s unique hydrogeologic conditions, from
alluvial basins to fractured bedrock, and the regulatory framework governing groundwater
management.
What is the primary driving force for groundwater flow according to Darcy's Law?
A) Capillary pressure
B) Hydraulic gradient
C) Atmospheric pressure
D) Vapor pressure
CORRECT ANSWER: B
EXPERT RATIONALE: Hydraulic gradient, defined as the difference in hydraulic head per
unit distance, is the main force driving groundwater flow in aquifers according to
Darcy's Law.
QUESTION 2
Which of the following best describes specific yield?
A) Total water held by the soil matrix
B) Water that drains from saturated material under gravity
C) Water bound to soil particles by molecular attraction
D) The hydraulic head of a saturated zone
CORRECT ANSWER: B
,2|Page
EXPERT RATIONALE: Specific yield is the volume of water that drains from a saturated
soil or rock due to gravity, expressed as a percentage of the total volume.
QUESTION 3
The zone between the water table and the land surface is called the:
A) Capillary fringe
B) Phreatic zone
C) Vadose zone
D) Saturated zone
CORRECT ANSWER: C
EXPERT RATIONALE: The vadose zone is the unsaturated region above the water table
where pore spaces contain both air and water.
QUESTION 4
Which of the following is a characteristic of a confined aquifer?
A) It receives recharge directly from precipitation above
B) It always has a water table
C) It is bounded above and below by low-permeability layers
D) It is found only in fractured rock formations
CORRECT ANSWER: C
EXPERT RATIONALE: Confined aquifers are overlain and underlain by confining units
(aquitards or aquicludes), which restrict vertical flow into or out of the aquifer.
QUESTION 5
According to the California Water Code Section 13750, what requirement applies to well
construction?
A) Wells must be constructed only by registered geologists
B) Wells must be constructed in a manner that prevents contamination of groundwater
,3|Page
C) All wells must be at least 500 feet deep
D) Well construction permits are valid for 10 years
CORRECT ANSWER: B
EXPERT RATIONALE: The California Water Code requires that wells be constructed to
prevent pollution or contamination of groundwater, which is the fundamental purpose
of well construction regulations.
QUESTION 6
What does a type curve in the Theis method represent?
A) A permeability trend line from pumping test data
B) A drawdown solution for an ideal confined aquifer
C) An empirical data regression for unconfined aquifers
D) A geochemical plume contour for contaminant transport
CORRECT ANSWER: B
EXPERT RATIONALE: The Theis type curve is a theoretical solution used to match
actual drawdown data to determine aquifer properties in confined aquifers .
QUESTION 7
Which ion is commonly used as a conservative tracer in groundwater studies?
A) Calcium
B) Nitrate
C) Chloride
D) Iron
CORRECT ANSWER: C
EXPERT RATIONALE: Chloride is a conservative ion that does not readily degrade,
adsorb, or participate in reactions in most aquifer systems, making it an ideal tracer .
, 4|Page
QUESTION 8
If a pumping test yields a transmissivity value of 150 m²/day and the saturated
thickness is 15 m, what is the hydraulic conductivity?
A) 0.1 m/day
B) 10 m/day
C) 2250 m/day
D) 1 m/day
CORRECT ANSWER: B
EXPERT RATIONALE: Hydraulic conductivity = Transmissivity / Saturated Thickness =
150 m²/day ÷ 15 m = 10 m/day .
QUESTION 9
Which geologic material typically has the lowest permeability?
A) Sandstone
B) Clay
C) Gravel
D) Fractured limestone
CORRECT ANSWER: B
EXPERT RATIONALE: Clay particles are very small and tightly packed, with tiny pore
spaces that significantly limit water movement, resulting in very low permeability .
QUESTION 10
What process most contributes to saltwater intrusion in coastal aquifers?
A) Natural tidal fluctuations
B) Thermal expansion of ocean water
C) Overpumping of freshwater aquifers
D) Sea level rise only
CORRECT ANSWER: C
