100+ Free InterNACHI Well Practice Questions

Pass your InterNACHI Certified Well Inspector exam on the first try — instant access, no signup required.

✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately

100+ Questions

100% Free

1 / 100

Question 1

Score: 0/0

Which sample location is GENERALLY preferred for a 'baseline' bacteriological test of well water on a real-estate inspection?

The water heater drain valve

The toilet tank

An outdoor hose bibb (after flushing and disinfecting)

The sump pump discharge

to track

Same family resources

Explore More InterNACHI Home Inspector Certification

Continue into nearby exams from the same family. Each card keeps practice questions, study guides, flashcards, videos, and articles in one place.

2026 Statistics

Key Facts: InterNACHI Well Exam

10 ppm

EPA Nitrate MCL

EPA National Primary Drinking Water Regulations

30 hrs

Coliform Sample Hold Time

EPA Drinking Water Sample Collection guidance

30/50 psi

Common Pressure Switch

Standard residential well-pump configuration

≥4 gpm

Recommended Well Yield

USDA Rural Development residential well guidance

Final Exam Questions

InterNACHI Certified Well Inspector

Exam Fee

Free for InterNACHI members

InterNACHI's Certified Well Inspector credential trains home inspectors to evaluate private drinking-water wells end-to-end. Expect questions on confined vs unconfined aquifers, well construction and casing materials, submersible vs jet pumps, pressure-switch settings (commonly 30/50 or 40/60 psi), EPA MCLs (nitrate >10 ppm is unsafe), sterile sampling with 30-hour lab hold times, treatment options (softener, RO, UV, neutralizer), and 4-hour/24-hour yield tests.

Sample InterNACHI Well Practice Questions

Try these sample questions to test your InterNACHI Well exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which type of well is created by driving a small-diameter pipe with a hardened drive point and screen into unconsolidated material?

A.Drilled well

B.Dug well

C.Driven well

D.Artesian well

Explanation: A driven well is created by driving a small-diameter pipe with a hardened drive point and perforated screen into unconsolidated material such as sand or gravel. They are typically shallow (under 50 ft) and limited to unconfined water-table aquifers.

2An aquifer that is bounded above and below by impermeable layers and is under pressure is called what?

A.Unconfined aquifer

B.Confined (artesian) aquifer

C.Perched aquifer

D.Water-table aquifer

Explanation: A confined aquifer is sandwiched between impermeable confining layers, placing it under pressure. When a well penetrates a confined aquifer, water rises above the top of the aquifer; if it rises above ground level it produces a flowing artesian well.

3Which well type is MOST susceptible to surface contamination and seasonal water-level fluctuation?

A.Deep drilled well in a confined aquifer

B.Driven well in unconsolidated sand

C.Dug well

D.Drilled well sealed with neat cement grout

Explanation: Dug wells have a large diameter, are very shallow, and typically draw from the water table, so they are the most susceptible to surface runoff contamination and to seasonal drops in the water table that can leave them dry.

4The water table is BEST defined as which of the following?

A.The depth at which the well screen is installed

B.The upper surface of the saturated zone in an unconfined aquifer where pore pressure equals atmospheric pressure

C.The static water level inside any well casing

D.The bottom of the well bore

Explanation: The water table is the upper boundary of the saturated zone in an unconfined aquifer, where the water pressure equals atmospheric pressure. It fluctuates seasonally with recharge and pumping.

5A drilled residential well in stable bedrock typically reaches what depth range compared with a dug well?

A.Shallower than a dug well

B.About the same depth

C.Much deeper, often 100 ft or more

D.Only 10 to 20 ft deeper

Explanation: Drilled wells routinely reach depths of 100 ft to several hundred feet, far deeper than dug wells (typically under 30 ft) or driven wells (typically under 50 ft). Greater depth means access to more reliable confined aquifers.

6In an unconfined aquifer, the static water level in a well will be at what elevation?

A.Above the top of the aquifer due to artesian pressure

B.Coincident with the local water table

C.At the bottom of the well bore

D.At ground surface regardless of conditions

Explanation: In an unconfined aquifer, the static water level inside a well coincides with the water table because the aquifer is at atmospheric pressure. There is no confining layer to produce artesian rise.

7Which feature distinguishes a flowing artesian well from a non-flowing artesian well?

A.Both draw from unconfined aquifers

B.The aquifer's potentiometric surface is above ground level at the well location

C.It uses a submersible pump rather than a jet pump

D.It is driven instead of drilled

Explanation: Both flowing and non-flowing artesian wells tap confined aquifers. A flowing artesian well exists where the potentiometric (pressure) surface is above ground level at the well, so water flows out without pumping. A non-flowing artesian well has its potentiometric surface above the aquifer but below ground.

8Recharge to an unconfined aquifer occurs PRIMARILY by which mechanism?

A.Vertical infiltration of precipitation through the unsaturated zone

B.Lateral flow from confined aquifers

C.Upwelling from deeper bedrock fractures

D.Surface runoff that bypasses the soil

Explanation: Unconfined aquifers are recharged primarily by vertical infiltration of precipitation through the unsaturated (vadose) zone. This direct hydrologic link is what makes unconfined aquifers responsive to drought and vulnerable to surface contamination.

9Driven wells are typically limited to what maximum depth range due to construction method?

A.Less than 50 ft

B.100-200 ft

C.Greater than 300 ft

D.Up to 1,000 ft

Explanation: Driven wells are usually less than 50 ft deep because the small-diameter pipe is physically driven into unconsolidated soil. They cannot penetrate bedrock or dense clay, which limits the technique to shallow unconfined aquifers.

10A confining layer above an aquifer is typically composed of which material?

A.Sand and gravel

B.Fractured bedrock

C.Clay or unfractured shale

D.Sandstone

Explanation: Clay and unfractured shale have very low hydraulic conductivity and act as confining layers (aquitards) that trap underlying aquifers under pressure. Sand, gravel, fractured rock, and sandstone are typically aquifer materials, not confining layers.

About the InterNACHI Well Exam

The InterNACHI Certified Well Inspector designation is awarded to inspectors who complete the free online How to Inspect Private Drinking Water Wells course and pass the 90-question multiple-choice final exam. The curriculum covers private drinking-water wells: well types and hydrogeology, components (cap, casing, grout seal, pitless adapter), pumps and pressure systems, water-quality testing against EPA MCLs, sampling procedures, treatment systems, and yield and recovery testing.

Questions

90 scored questions

Time Limit

Self-paced

Passing Score

Weighted; ~80 cut-off

Exam Fee

Free for InterNACHI members (InterNACHI (International Association of Certified Home Inspectors))

InterNACHI Well Exam Content Outline

~28%

Well Construction & Components

Well types (drilled, dug, driven), aquifers, casing, grout, sanitary seal, vent, and pitless adapter.

~16%

Pumps & Pressure Systems

Submersible and jet pumps, pressure tanks, pressure switches, and drawdown.

~30%

Water Quality & Sampling

EPA contaminant standards, coliform/nitrate/arsenic/lead, sterile bottles, and chain of custody.

~14%

Treatment Systems

Softeners, reverse osmosis, UV disinfection, sediment filters, and acid neutralizers.

~12%

Yield & Recovery Testing

Flow rate, drawdown, recovery, 4-hour and 24-hour sustained-yield tests.

How to Pass the InterNACHI Well Exam

What You Need to Know

Passing score: Weighted; ~80 cut-off
Exam length: 90 questions
Time limit: Self-paced
Exam fee: Free for InterNACHI members

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

InterNACHI Well Study Tips from Top Performers

1Memorize EPA MCLs: nitrate 10 mg/L (as N), arsenic 0.010 mg/L, lead action level 0.015 mg/L, total coliform must be absent

2Know the difference between confined (artesian) and unconfined (water-table) aquifers and how each affects well yield

3Distinguish well types: drilled (deepest, cased), dug (shallow, large diameter), driven (small diameter, unconsolidated material)

4Understand pump selection: shallow jet pumps for water <25 ft, deep jet up to ~100 ft, submersible for deeper wells

5Memorize pressure-switch ranges (30/50 and 40/60 psi) and how they cycle the pump on and off

6Master sampling: sterile bottle, do not rinse, do not touch the inside, flush faucet ~5 minutes, deliver on ice within 30 hours

7Know the treatment train: sediment → iron → acid neutralizer → softener → carbon → UV (UV is last, downstream of all particulate)

8Understand yield testing: 4-hour and 24-hour pump tests measure sustainable yield, drawdown, and recovery rate

Frequently Asked Questions

What is the InterNACHI Certified Well Inspector certification?

The InterNACHI Certified Well Inspector designation is awarded by the International Association of Certified Home Inspectors to members who complete InterNACHI's free online How to Inspect Private Drinking Water Wells course and pass the 90-question final exam. It qualifies inspectors to evaluate private drinking-water well systems — including well construction, components, pumps, water quality, and yield — as part of or alongside a home inspection.

How long is the InterNACHI Well Inspector exam and how is it scored?

The InterNACHI Well Inspector exam is 90 multiple-choice questions drawn from a larger pool. The exam is self-paced and delivered online through nachi.org. Scoring is weighted by topic area, with a typical cut-off near 80%. Members can retake the exam after review without a mandatory waiting period.

What does the InterNACHI Well Inspector exam cover?

The exam covers private drinking-water wells: well types (drilled, dug, driven) and hydrogeology (confined vs unconfined aquifers, water table); components (well cap, casing, screen, grout/sanitary seal, vent, pitless adapter, frost protection); pumps (submersible vs jet, shallow vs deep) and pressure systems (pressure tank, pressure switch settings such as 30/50 psi); water quality testing against EPA standards (coliform, E. coli, nitrate >10 ppm, arsenic, lead, radon, hardness, pH, TDS); sampling procedures (sterile bottle, faucet flushing, chain of custody, lab hold time within ~30 hours); treatment systems (water softener/ion exchange, reverse osmosis, UV disinfection, sediment filter, acid neutralizer); and yield/recovery testing (flow rate, drawdown, 4-hour and 24-hour yield).

How much does the InterNACHI Well Inspector course and exam cost?

Both the How to Inspect Private Drinking Water Wells course and the certification exam are free for active InterNACHI members. InterNACHI membership itself is approximately $49/month with discounted annual rates. There is no per-attempt exam fee and the online exam can be retaken.

Is the InterNACHI Well Inspector certification recognized for licensing?

Well-inspection licensing varies by state. Some states require separate certification for well or potable-water-system inspection, water-sample collection, or septic/private water inspections. The InterNACHI Certified Well Inspector designation is widely recognized for marketing and continuing education, but always verify your state and county requirements before performing or charging for well inspections.

Do well inspectors collect their own water samples?

Many well inspectors collect samples for laboratory analysis as part of an inspection, but some states or counties require a separately certified water-sample collector. When sampling is allowed, inspectors must use sterile bottles, flush the faucet for several minutes, avoid touching the inside of the bottle or cap, document chain of custody, keep samples on ice, and deliver them to a certified lab within the required hold time — generally 30 hours for drinking-water coliform samples.

100+ Free InterNACHI Well Practice Questions

Explore More InterNACHI Home Inspector Certification

CCPIA Certified Commercial Property Inspector

InterNACHI / IAC2 Certified Mold Inspector

InterNACHI Certified 11th-Month Warranty Inspector

InterNACHI Certified Deck Inspector

InterNACHI Certified Home Energy Auditor

InterNACHI Certified Mold Inspector