CO Well Driller common mistakes
CO Well Driller · Understand the traps and how to avoid them.
Treating the well-construction quiz items as general plumbing knowledge and answering from field habit instead of from the state well-construction rules, e.g. choosing a casing depth because 'that is what we always set' rather than the depth the regulation specifies for the stated overburden and use.
Experienced drillers rely on routines that may predate current rule revisions or may be local practice rather than statewide minimums; the exam tests the codified minimum, not the customary one.
What to do instead
Build a one-page table of the numeric requirements you are most likely to be tested on (minimum casing length and thickness by use, annular seal depth and material, grout placement method, minimum setback distances, disinfection and sampling timing) and cite the rule section beside each number. Drill until you can state each value and its condition without notes.
Confusing the sequence and method of annular seal placement: answering that grout may be poured from the surface, or that the seal can be placed before the casing is centered, or reversing the order of drilling, casing, sealing, and development in a described scenario.
The steps are learned as a continuous field routine, so candidates remember the individual actions but not the dependencies the exam is probing, especially the requirement to place seal material from the bottom up through a tremie or similar method.
What to do instead
Write the construction sequence as a numbered flow for a shallow well and a deep well, and mark at each step what must already be true. Practice scenario questions by crossing out any answer option that has a step out of order before evaluating the remaining options on technical merit.
On ground heat exchanger items, applying water-well casing and grouting rules unchanged to a closed-loop borehole, or vice versa, without checking which construction standard the question is describing.
Both involve drilling, casing, and sealing, so the vocabulary overlaps; candidates transfer familiar water-well answers to loop questions and miss loop-specific requirements such as grouting the full annulus and the handling of the loop pipe during sealing.
What to do instead
Make a two-column comparison of water-well versus closed-loop borehole requirements covering annular seal extent, grout material and thermal conductivity considerations, pipe testing and pressure-holding before and after grouting, and borehole abandonment. Answer each item by first naming which standard applies.
Skipping the pressure test and fluid-fill logic for loop fields: not recognizing when a loop must be pressure-tested, what the test pressure and duration should be relative to, and how the loop should be left pressurized during grouting.
These are inspection and paperwork steps that the field crew may perform without the driller reasoning through the acceptance criteria, so the candidate has seen it done but cannot state the conditions.
What to do instead
Memorize the test protocol as a short checklist: when the test occurs, what pressure is held, how long, what constitutes a passing result, and what must be documented. Then work through items where a scenario gives a pressure reading and asks whether the loop passes.
Mixing up pump-installation details: setting depth relative to the pump-setting or intake level, sizing the drop pipe and check valve arrangement, and the electrical supply requirements such as disconnect location, conductor protection, and bonding.
Installation knowledge is heavily hands-on and varies by job, so candidates answer from the last job they did rather than from the standard the exam cites, particularly on electrical items they rarely touch themselves.
What to do instead
Separate the topic into mechanical (setting depth, check valves, torque arrestors, drop pipe sizing, sanitary seal) and electrical (disconnect, overcurrent protection, bonding, wire sizing) and study them in separate sessions. For electrical items, learn the specific rule citation and the safety rationale, since exam distractors often describe a plausible but non-compliant shortcut.
Answering licensing-administration items from memory of how the office handled a renewal, rather than from the actual rule: misstating license term length, renewal timing and late consequences, continuing-education hours required per cycle, and the notification duties when a licensee changes address or employer.
These items feel administrative and low-risk, so candidates under-prepare, and the correct answers are precise numbers and deadlines that casual familiarity gets wrong.
What to do instead
Create a single reference sheet of administrative facts (term, renewal window, late fees or reinstatement path, CE hour totals and category limits, reporting deadlines) and self-test on the numbers weekly. Treat every numeric administrative item as a fact to be memorized, not inferred.
Treating financial-responsibility requirements as interchangeable: assuming any bond, letter of credit, or insurance policy satisfies the requirement without checking the required amount, the coverage type, or the filing and proof-of-continuity obligations.
Candidates lump all surety instruments together and may have only ever used one form, so they pick the option that sounds like what their company carries.
What to do instead
Learn the requirement as a set of attributes (minimum amount, acceptable instrument types, who must be covered, when proof must be filed, and what happens on cancellation or lapse) and evaluate each answer option against all attributes rather than recognizing a familiar term.
On continuing-education items, counting any training toward the requirement without checking whether the subject category, provider approval, or documentation is acceptable, and misjudging what happens when hours are short at renewal.
Candidates assume all relevant training counts equally and do not track category limits or approval status, so they choose answers that describe training they personally found useful.
What to do instead
Map the CE rule into a table of approved categories, per-category caps, provider-approval conditions, recordkeeping duties, and the consequence of a shortfall. Practice by classifying sample course descriptions as qualifying or not and stating the reason.
Approaching remedial-action scenarios as general customer-service problems, choosing the response that keeps the client happy rather than the sequence the rules require: notification, investigation, correction, and documentation within stated timeframes.
In the field the priority is resolving the complaint quickly, so candidates select the fastest-sounding remedy and overlook mandatory reporting or the order of steps.
What to do instead
Learn remedial action as a fixed sequence with deadlines attached to each step, and for each practice scenario write the required steps in order before looking at the options. Eliminate any option that skips notification or documentation even if the technical remedy sounds right.
Managing time poorly across the exam by lingering on calculation or scenario items and then rushing the short factual items, leaving easy administrative and CE points unanswered or changed on a second guess.
Construction and loop scenarios invite over-thinking, and candidates who feel strongest on field topics spend disproportionate time there while under-valuing the quick factual domains.
What to do instead
Before the exam, decide a per-item time budget and a rule for flagging and moving on. In practice sets, do full-length timed runs and record which domains consume your time; if administrative or CE items are your fastest points, answer them first in each pass so they are never sacrificed to the clock.