Guidelines for Successful Water Well Maintenance

Wells that succeed the longest are the ones that follow a proper maintenance plan.

By Michael Schnieders, PG, PH-GW

Despite similarities, water wells are individual systems operating within dynamic and often complex environments.

For contractors and groundwater professionals alike, successful water well maintenance is not simply a matter of reacting to declining performance; it is the integration of diagnostics, hydraulics, physics, and materials science into a proactive asset management strategy.

Wells that are properly designed, regularly monitored, and routinely maintained can operate efficiently for decades, while neglected wells often suffer accelerated fouling impacting water quality and capacity, resulting in costly rehabilitation.

This article will outline guidelines and best practices for sustaining performance, protecting the well structure, and maximizing the resource long term.

Working with a Baseline

The author, pictured at Groundwater Week 2025, has spoken on the topic of well maintenance at groundwater events around the country.

Successful maintenance begins with accurate baseline data. Immediately after completion (including development), information should have been filed with the state recording the well design, the static and pumping water levels, the yield, and a few key water quality parameters. This information is useful to identify what has changed in the time since completion.

Identifying the well’s current capacity and noting any observed changes either at the surface or within the use/treatability of the produced water is a great first start. At this time, it is also advisable to collect a water sample and compare the water quality with the historical data on file.

Like how the operational data (flow rate, specific capacity, etc.) can tell us how impacted the well is, a water analysis can give us insight into any chemical or biological changes that may be occurring downhole. Ideally, this sort of periodic well health analysis has occurred regularly since the well was completed. Trend analysis is far more valuable than isolated measurements.

A gradual increase in drawdown at constant pumping rate, rising discharge pressure, declining specific capacity, or increasing amperage can signal screen plugging, encrustation, or pump wear long before catastrophic failure. Likewise, upward trends in iron, calcium hardness, or the bacterial population may indicate early-stage fouling before water quality or the production is impacted.

Making a Correct Diagnosis

Effective maintenance depends on correctly diagnosing the dominant fouling mechanism impacting the well. Most wells experience one or more of the following:

• Mineral Encrustation: Calcium carbonate, iron and manganese oxides, and calcium sulfate can accumulate on perforations (screens) and within filter packs or fractures, reducing effective open area and increasing head loss.
• Biofouling: Slime-forming bacteria including common species such as Pseudomonas and Bacillus generate extracellular polymeric substances referred to as biofilm that trap particulate and accelerate plugging. As biofouling increases, the populations can become more problematic, developing anaerobic growth within the community. In addition to harboring environmental coliforms,
  heavier anaerobic activity can include sulfate-reducing bacteria (SRB), which produce hydrogen sulfide, contribute to microbiologically influenced corrosion (MIC), and odor and taste problems.
• Sediment Infiltration: Fine sediments including sand, silt, and clay can migrate over time into the bore, impacting production and drawdown.
• Iron-Related Fouling: Separated from typical chemical and biological means due to its common role in impacting wells and associated systems. Iron fouling can be a result of corrosion, formation influence, and microbial activity.

A successful maintenance program addresses the root cause—not merely the symptoms. For example, aggressively acidizing a well dominated by iron bacteria without addressing biofilm will yield only temporary improvement and could drive corrosion tendencies to worsen the issue.

Using Mechanical and Chemical Means

Mechanical measures used as a means of pre-treatment remain an important part of any maintenance program. Physical disruption and subsequent removal of the disrupted debris help to remove bulk material from the well, improving the activity and cost of follow-up chemical or mechanical efforts.

Brushing, surging, jetting, and pressurized gas injections are some of the tools used to mechanically clean wells. Brushing with a nylon or soft metal brush remains a very effective means when addressing biofouling in new and old wells alike. The higher tensile-strength splayed cable brushes can create additional reactive surfaces downhole, impacting the well long term.

Chemical cleaning is a means of harnessing chemical reactions, which can be good (dissolving calcium scale) or can be bad (corrosion attack of low carbon steel). The use of chemicals should be based on understanding what types of fouling are downhole and what condition the well structure is in.

• Oxidizing or Disinfection Agents: Chlorine (hypochlorite), chlorinated isocyanurates, chlorine dioxide, or hydrogen peroxide can reduce microbial populations but do little for mineral scale. Despite the lower cost and common application, use of oxidants can be dangerous, and overdosing may increase corrosion potential.
• Acid Treatments: Used for scale removal by solubilizing (dissolving) mineral encrustations. Acid type and strength, dosage rate, contact time, and inhibitor selection must be matched to the type of scale, material of well construction (e.g., stainless steel vs. low-carbon steel) and formation (geology).
• Dispersants, Surfactants, or Chelating Agents: Specialty polymers and wetting agents can be used to improve the effectiveness of oxidizers and acids, controlling scale-forming ions, improving dispersion, or limiting corrosion.

Monitoring the chemical reaction during treatment is just as important as the selection of products. Monitoring will be dependent on the selected chemicals and may include pH, conductivity, and concentration (e.g., high/low chlorine) as well as visual observations.

Wrapping Things Up

Once mechanical, chemical, or combined methods of treatment are complete, the well should be thoroughly evacuated. Flushing may require multiple well volumes, so prepare temporary containment ahead of time. Actively purge the entire well until both the water chemistry and visual conditions have returned to normal conductivity and an absence of visual turbidity.

Always neutralize away from the well and properly dispose of spent treatment fluids in accordance with local regulations. Post-treatment pumping and monitoring are essential to verify restoration of specific capacity and stabilization of water quality parameters. Keeping the well active while awaiting any required testing results is also a wise move to limit stagnation.

Once physical maintenance efforts are complete, document the event. Every maintenance event should produce a report documenting:

• Pre- and post-treatment performance metrics
• Water test results
• Mechanical and chemical methods applied
• Observations and confirmation monitoring during evacuation
• Recommendations for follow-up.

Successful water well ownership is a life-cycle-process. Initial design decisions—including screen selection, gravel pack sizing, pump setting depth, and material compatibility—directly influence long-term maintenance frequency and cost.

Ultimately, the most successful wells are not those that never foul; they are those that are systematically monitored with targeted maintenance conducted proactively. Combining sound diagnostics, preventive maintenance, and data-driven rehabilitation strategies—groundwater professionals can ensure sustainable and reliable well performance for decades.

Add This Resource to Your Toolbox

The 2016 book, Operational Stage of the Well, whose coauthor is the author of this article, covers various factors of well deterioration and how they impact well operation and maintenance.

Through research, field work, and laboratory work, the authors have developed a method for assessing the information and assigning a value to the well regarding its health. The information can extend the operational lifespan of existing wells while providing valuable information into the design and operation of new well systems. Click here for more information.

Michael Schnieders, PG, PH-GW, is the president and principal hydrogeologist at Water Systems Engineering Inc. He has an extensive background in groundwater geochemistry, geomicrobiology, and water resource investigation and management. He specializes in the diagnosis and treatment of fouled wells and potable water systems. Schnieders is the 2017 McEllhiney Distinguished Lecturer in Water Well Technology. He can be reached at mschnieders@h2osystems.com.