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TEXAS WATER WELL DRILLER LICENSE PRACTICE EXAM
FULL PACKAGE QUESTIONS ANSWERS AND RATIONALES
2026-27 LATEST UPDATED VERSION
INSTANT DOWNLOAD PDF..!!
INTRODUCTION
The Texas Water Well Driller License Examination is a highly rigorous, state-mandated proctored assessment
administered under the strict jurisdiction of the Texas Department of Licensing and Regulation (TDLR) and
guided by the Texas Water Well Driller Advisory Council under the authority of Texas Occupations Code
Chapters 1901 and 1902, alongside Texas Administrative Code (TAC) Chapter 76. Obtaining a professional
water well driller license in Texas is an essential legal benchmark designed to safeguard the public welfare,
protect valuable state aquifers (such as the Edwards, Ogallala, and Carrizo-Wilcox systems) from contamination,
and ensure structural mechanical integrity in well construction.
Achieving a passing score requires an advanced mastery of hydrogeology, well logging, drilling mechanics
(including mud rotary, air rotary, and cable tool dynamics), casing calculations, disinfection methodologies, and
strict state isolation/setback tables. This comprehensive practice question bank has been developed to mirror
the exact scenario structures, regulatory thresholds, and technical complexities encountered on the official
TDLR proctored licensing exam. By focusing on critical safety factors and current Texas statutory mandates, this
study package ensures you will eliminate distracting choices and confidently secure your state professional
license on your very first attempt.
CORE DOMAINS TESTED
• Domain 1: Texas Statutes, Rules, and Administrative Procedures – Focuses on TAC Chapter 76, TDLR
enforcement actions, water well driller definitions, logging deadlines (60 days), and variance request
procedures.
• Domain 2: Well Site Selection and Regulatory Setback Matrices – Covers exact horizontal isolation
distances separating a well from contamination sources like septic drainfields (150 ft), concentrated
animal feeding operations, and property lines (5 ft).
• Domain 3: Drilling Mechanics, Rig Operations, and Formation Logging – Targets mud weight
calculations, bit tracking, air/fluid velocity ratios, lithology tracking, and identification of perched vs.
unconfined vs. artesian aquifer zones.
• Domain 4: Well Construction, Casing, and Annular Grouting Safety – Focuses on annular space
requirements, surface completion slabs, pitless adapter installation mechanics, and bentonite/cement
grout slurry density mixtures.
• Domain 5: Well Development, Disinfection, and Environmental Protection – Covers screen pack
geometry, gravel pack choices, sodium hypochlorite calculation thresholds (minimum 50 to 100 ppm
contact shock), and plugging procedures for abandoned wells.
,2
Q1: A licensed water well driller is preparing to construct a domestic
water well on a residential parcel in Texas. According to 16 Texas
Administrative Code (TAC) Chapter 76, what is the absolute minimum
horizontal setback distance that must separate a standard water well
from a conventional septic tank soil absorption field (drainfield) or an
organized septic spray area?
A) 50 feet
B) 100 feet
C) 150 feet of horizontal isolation distance to prevent pathogen and
nitrate contamination from the domestic effluent system.
D) 250 feet unless an official geophysical log is submitted to the local
groundwater conservation district.
Rationale: The correct answer is C because 16 TAC §76.100 explicitly
mandates that a water well must be located a minimum horizontal
distance of 150 feet from any concentrated source of contamination,
which directly includes septic tank drainfields, absorption beds,
sewage holding pits, and septic spray distribution zones. Option A
represents the setback between a well and a watertight septic tank
structure itself (50 feet), not the absorption field. Options B and D
reflect non-compliant figures that violate standard Texas water
quality safety tables.
Q2: During a mud rotary drilling operation in a loose, unconsolidated
sand-and-gravel formation, the driller notes a sudden, significant loss
of drilling fluid volume in the pits, accompanied by a drop in
circulating pressure. Which of the following drilling fluid
modifications is most appropriate to resolve this lost circulation
event?
A) Significantly increase the rotational speed (RPM) of the drill string
and add fresh water to lower viscosity.
B) Incorporate lost circulation materials (LCM) such as bentonite
,3
chips, mica, or cellulose fibers into the drilling mud to seal the high-
permeability thief zones.
C) Double the weight of the drilling mud by adding pure barite to
force the fluid out of the borehole.
D) Switch the rig immediately to a high-pressure compressed air
drilling vector without removing the bit.
Rationale: The correct answer is B. A sudden loss of fluid volume and
pressure when penetrating loose sand or fractured formations
indicates a "lost circulation" event, where drilling mud escapes into
highly porous or fractured "thief zones." Incorporating lost circulation
materials (LCM) into the mud slurry helps block and bridge these
structural voids, forming a temporary filter cake that stabilizes the
borehole wall and restores circulation. Option A will worsen hole
erosion. Option C increases hydrostatic pressure, which will force
even more mud into the formation gaps. Option D is highly dangerous
without a properly configured air rig setup and clear clearance
vectors.
Q3: A licensed driller finishes a 350-foot deep domestic water well in
Texas and installs a standard PVC casing string. According to TDLR
regulations, what is the maximum time window permitted following
well completion for the driller to submit a complete, official Water
Well Driller’s Report (State Well Log) to the department and the
owner?
A) 10 business days
B) 30 calendar days
C) 60 calendar days from the date the drilling and completion work
is officially finished.
D) 90 calendar days provided a temporary waiver is filed with the
local Groundwater Conservation District (GCD).
Rationale: The correct answer is C. Under 16 TAC §76.70, a licensed
, 4
driller must complete and deliver a legible Water Well Driller's Report
to the TDLR, the Texas Water Development Board (TWDB), and the
well owner within 60 days of well completion. Failure to log and file
this report within this specific statutory timeframe constitutes an
administrative violation and can trigger enforcement actions,
penalties, or license suspension. Options A, B, and D describe
timelines that are legally non-compliant.
Q4: An installer is setting a thermoplastic (PVC) water well casing
down a 200-foot deep borehole. According to 16 TAC Chapter 76
casing standards, what is the minimum required Standard Dimension
Ratio (SDR) or wall thickness classification permitted for plastic well
casing installed in the state of Texas?
A) SDR 41
B) SDR 26 or heavier (such as SDR 21 or Schedule 80) to ensure
adequate collapse resistance against annular hydrostatic pressures
and grouting thermal shifts.
C) Schedule 40 thin-wall structural conduit
D) Any standard agricultural drainage pipe is permitted if wrapped in
geotextile fabric.
Rationale: The correct answer is B. Texas regulations specify that
thermoplastic water well casing must meet or exceed a rating of SDR
26 to guarantee sufficient structural collapse strength against the
lateral pressures exerted by the surrounding formation and heavy
bentonite/cement grout columns. Using thin-walled materials like
SDR 41 or basic unrated conduit (Options A and C) risks casing
collapse during the thermal curing phase of cementing or structural
shift events. Option D describes non-compliant materials strictly
prohibited by TDLR sanitational standards.
Q5: A driller is completing the annular seal for a domestic water well
to prevent the downward migration of surface contaminants.
TEXAS WATER WELL DRILLER LICENSE PRACTICE EXAM
FULL PACKAGE QUESTIONS ANSWERS AND RATIONALES
2026-27 LATEST UPDATED VERSION
INSTANT DOWNLOAD PDF..!!
INTRODUCTION
The Texas Water Well Driller License Examination is a highly rigorous, state-mandated proctored assessment
administered under the strict jurisdiction of the Texas Department of Licensing and Regulation (TDLR) and
guided by the Texas Water Well Driller Advisory Council under the authority of Texas Occupations Code
Chapters 1901 and 1902, alongside Texas Administrative Code (TAC) Chapter 76. Obtaining a professional
water well driller license in Texas is an essential legal benchmark designed to safeguard the public welfare,
protect valuable state aquifers (such as the Edwards, Ogallala, and Carrizo-Wilcox systems) from contamination,
and ensure structural mechanical integrity in well construction.
Achieving a passing score requires an advanced mastery of hydrogeology, well logging, drilling mechanics
(including mud rotary, air rotary, and cable tool dynamics), casing calculations, disinfection methodologies, and
strict state isolation/setback tables. This comprehensive practice question bank has been developed to mirror
the exact scenario structures, regulatory thresholds, and technical complexities encountered on the official
TDLR proctored licensing exam. By focusing on critical safety factors and current Texas statutory mandates, this
study package ensures you will eliminate distracting choices and confidently secure your state professional
license on your very first attempt.
CORE DOMAINS TESTED
• Domain 1: Texas Statutes, Rules, and Administrative Procedures – Focuses on TAC Chapter 76, TDLR
enforcement actions, water well driller definitions, logging deadlines (60 days), and variance request
procedures.
• Domain 2: Well Site Selection and Regulatory Setback Matrices – Covers exact horizontal isolation
distances separating a well from contamination sources like septic drainfields (150 ft), concentrated
animal feeding operations, and property lines (5 ft).
• Domain 3: Drilling Mechanics, Rig Operations, and Formation Logging – Targets mud weight
calculations, bit tracking, air/fluid velocity ratios, lithology tracking, and identification of perched vs.
unconfined vs. artesian aquifer zones.
• Domain 4: Well Construction, Casing, and Annular Grouting Safety – Focuses on annular space
requirements, surface completion slabs, pitless adapter installation mechanics, and bentonite/cement
grout slurry density mixtures.
• Domain 5: Well Development, Disinfection, and Environmental Protection – Covers screen pack
geometry, gravel pack choices, sodium hypochlorite calculation thresholds (minimum 50 to 100 ppm
contact shock), and plugging procedures for abandoned wells.
,2
Q1: A licensed water well driller is preparing to construct a domestic
water well on a residential parcel in Texas. According to 16 Texas
Administrative Code (TAC) Chapter 76, what is the absolute minimum
horizontal setback distance that must separate a standard water well
from a conventional septic tank soil absorption field (drainfield) or an
organized septic spray area?
A) 50 feet
B) 100 feet
C) 150 feet of horizontal isolation distance to prevent pathogen and
nitrate contamination from the domestic effluent system.
D) 250 feet unless an official geophysical log is submitted to the local
groundwater conservation district.
Rationale: The correct answer is C because 16 TAC §76.100 explicitly
mandates that a water well must be located a minimum horizontal
distance of 150 feet from any concentrated source of contamination,
which directly includes septic tank drainfields, absorption beds,
sewage holding pits, and septic spray distribution zones. Option A
represents the setback between a well and a watertight septic tank
structure itself (50 feet), not the absorption field. Options B and D
reflect non-compliant figures that violate standard Texas water
quality safety tables.
Q2: During a mud rotary drilling operation in a loose, unconsolidated
sand-and-gravel formation, the driller notes a sudden, significant loss
of drilling fluid volume in the pits, accompanied by a drop in
circulating pressure. Which of the following drilling fluid
modifications is most appropriate to resolve this lost circulation
event?
A) Significantly increase the rotational speed (RPM) of the drill string
and add fresh water to lower viscosity.
B) Incorporate lost circulation materials (LCM) such as bentonite
,3
chips, mica, or cellulose fibers into the drilling mud to seal the high-
permeability thief zones.
C) Double the weight of the drilling mud by adding pure barite to
force the fluid out of the borehole.
D) Switch the rig immediately to a high-pressure compressed air
drilling vector without removing the bit.
Rationale: The correct answer is B. A sudden loss of fluid volume and
pressure when penetrating loose sand or fractured formations
indicates a "lost circulation" event, where drilling mud escapes into
highly porous or fractured "thief zones." Incorporating lost circulation
materials (LCM) into the mud slurry helps block and bridge these
structural voids, forming a temporary filter cake that stabilizes the
borehole wall and restores circulation. Option A will worsen hole
erosion. Option C increases hydrostatic pressure, which will force
even more mud into the formation gaps. Option D is highly dangerous
without a properly configured air rig setup and clear clearance
vectors.
Q3: A licensed driller finishes a 350-foot deep domestic water well in
Texas and installs a standard PVC casing string. According to TDLR
regulations, what is the maximum time window permitted following
well completion for the driller to submit a complete, official Water
Well Driller’s Report (State Well Log) to the department and the
owner?
A) 10 business days
B) 30 calendar days
C) 60 calendar days from the date the drilling and completion work
is officially finished.
D) 90 calendar days provided a temporary waiver is filed with the
local Groundwater Conservation District (GCD).
Rationale: The correct answer is C. Under 16 TAC §76.70, a licensed
, 4
driller must complete and deliver a legible Water Well Driller's Report
to the TDLR, the Texas Water Development Board (TWDB), and the
well owner within 60 days of well completion. Failure to log and file
this report within this specific statutory timeframe constitutes an
administrative violation and can trigger enforcement actions,
penalties, or license suspension. Options A, B, and D describe
timelines that are legally non-compliant.
Q4: An installer is setting a thermoplastic (PVC) water well casing
down a 200-foot deep borehole. According to 16 TAC Chapter 76
casing standards, what is the minimum required Standard Dimension
Ratio (SDR) or wall thickness classification permitted for plastic well
casing installed in the state of Texas?
A) SDR 41
B) SDR 26 or heavier (such as SDR 21 or Schedule 80) to ensure
adequate collapse resistance against annular hydrostatic pressures
and grouting thermal shifts.
C) Schedule 40 thin-wall structural conduit
D) Any standard agricultural drainage pipe is permitted if wrapped in
geotextile fabric.
Rationale: The correct answer is B. Texas regulations specify that
thermoplastic water well casing must meet or exceed a rating of SDR
26 to guarantee sufficient structural collapse strength against the
lateral pressures exerted by the surrounding formation and heavy
bentonite/cement grout columns. Using thin-walled materials like
SDR 41 or basic unrated conduit (Options A and C) risks casing
collapse during the thermal curing phase of cementing or structural
shift events. Option D describes non-compliant materials strictly
prohibited by TDLR sanitational standards.
Q5: A driller is completing the annular seal for a domestic water well
to prevent the downward migration of surface contaminants.
