Why Test Wells Should Often Be the Last Step, Not the First Step of Water Well Location.

By Ervin M. Kraemer

One of the most common misconceptions in groundwater development is the belief that drilling a test well should be the first step in evaluating a property.

While test wells play an important role in water resource development, they are often most valuable after preliminary exploration has been completed—not before.

After more than 25 years working with groundwater exploration projects, I have seen many situations where property owners, developers, agricultural operations, and municipalities invested significant resources into test drilling without first gathering sufficient information about whether a groundwater-bearing zone was present, how deep it might be, how thick it might be, how laterally continuous it might be, or where the most favorable drilling location existed on the property.

The result is often unnecessary expense, increased uncertainty, and, in some cases, disappointing outcomes.

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What Is a Test Well?

A test well is a borehole drilled (often a smaller diameter than a production well) to gather information about groundwater conditions and aquifer characteristics. Test wells are commonly used to verify aquifer properties, conduct pumping tests, evaluate water quality, and assist with final well design.

Test wells provide valuable information. However, they also have limitations. A test well only provides information about the specific location where it is drilled. Even a productive test well does not necessarily indicate that the chosen location represents the best groundwater target on a property. Likewise, a poor test well does not automatically mean that groundwater resources are absent from the surrounding area.

Why Test Wells Became the Industry Standard

For decades, test wells were one of the most practical tools available for evaluating groundwater resources. Before the development of advanced exploration technologies, drilling was often the only way to obtain direct information about subsurface conditions. As a result, test drilling became a standard part of groundwater development in many regions and remains an important tool today.

There is a good reason for that history. A drilled hole provides direct physical information that cannot always be obtained any other way. However, exploration technology continues to evolve. Today, modern exploration methods can often provide valuable information before a test well is drilled, helping evaluate potential groundwater-bearing zones, focus drilling efforts, and reduce uncertainty during project planning.

This shift allows test wells to serve one of their most valuable roles: verification and development of a targeted groundwater resource rather than functioning as the primary exploration tool.

The Cost of Exploration by Drilling Alone

Drilling is often one of the most expensive methods of gathering subsurface information. Depending on depth, geology, casing requirements, and local conditions, a test well can represent a substantial investment before a production well is ever constructed.

When drilling becomes the primary exploration tool, the process can quickly become one of elimination rather than informed decision-making. Every hole drilled provides information, but each hole also requires time, money, labor, fuel, equipment, and land disturbance.

For this reason, many project owners are increasingly interested in exploration methods that can help narrow target areas before drilling begins.

The Role of Modern Exploration

The purpose of exploration is to reduce uncertainty before drilling begins. Modern exploration technologies can help evaluate whether a groundwater-bearing zone is present, its approximate depth, thickness, lateral continuity, and potential suitability for well development before significant drilling expenditures are made.

No exploration method eliminates risk, and no responsible professional should suggest otherwise. However, gathering information before drilling often improves decision-making and helps focus attention on the most favorable target areas.

Throughout my 25 year career, much of my work has involved the practical application of seismoelectric exploration technology through AquaLocate®. Unlike methods designed primarily to image geological structure, seismoelectric systems are designed to respond to mobile resistive fluids, helping evaluate potential freshwater-bearing zones before drilling decisions are made.

The objective is not to replace drilling. The objective is to improve drilling decisions.

Environmental and Economic Considerations

Another advantage of pre-drill exploration is that it may help reduce unnecessary land disturbance. Every exploratory borehole requires equipment mobilization, site preparation, fuel consumption, and physical alteration of the site. While drilling remains an essential part of groundwater development, reducing unnecessary drilling can benefit both project economics and environmental stewardship.

In many situations, gathering more information before drilling can be both financially practical and environmentally responsible.

Exploration and Drilling Work Together

Successful groundwater development is rarely the result of a single tool or a single piece of information. Exploration, test drilling, well construction, well development, and pump testing all play important roles in the process.

The question is not whether drilling is necessary. The question is when drilling should occur and how much information is available before the drill bit enters the ground.

In many projects, the most effective approach is to gather as much reliable information as possible before committing to a drilling location.

Dig Well Drilling Co. conducting a pre-drill seismoelectric groundwater survey to ensure a productive well drilling the first time around for his clients.

“I’ve been utilizing AquaLocate’s water location technology since 2013 and I am truly impressed with the results. The owners have been exceptional to work with, always making us feel valued and understood, not just like another customer.” — Trinity Villines, Dig Well Drilling

The Goal Is Not Simply to Drill a Well

The goal is to develop a successful water supply. That distinction matters.

One reason I wrote Water Well Drilling – A Comprehensive Guide to Proper Construction was to help property owners better understand the well construction process and the many factors that influence project success. The drilling process itself is only one part of a successful groundwater project. Site selection, resource evaluation, well development, and long-term performance are equally important.

For property owners, agricultural operations, municipalities, and commercial projects alike, informed decisions often produce better outcomes than decisions based solely on assumptions or limited information.

The goal is not simply to drill a hole.

The goal is to drill a successful water well at the right location - the first time around!

About the Author

Ervin Michael Kraemer is the founder of AquaLocate® and PetroLocate®, author, inventor, trainer, and a recognized subject matter expert in groundwater and hydrocarbon exploration. He is the author of Water Well Drilling: A Comprehensive Guide to Proper Construction and Seismoelectric Exploration: A Practical Guide to Direct Fluid Detection. For more than 25 years, he has trained and consulted with operators and clients involved in exploration projects across six continents, helping advance the practical application of seismoelectric technology for groundwater and hydrocarbon evaluation.