Annual Costs of Secondary Disinfection including Copper Silver Ionization (CSI), Mixed Oxidant, Monochloramines & Chlorine Dioxide

Get a clear picture of what secondary (or supplemental) disinfection will cost for your facility should you choose to add a system. At Legionella Control Systems, we work with proven disinfection systems: mixed oxidant solution (MOS), copper-silver ionization (CSI), chlorine dioxide, and monochloramines. Every system involves rental, maintenance, parts, engineering design, and ongoing support. Note: Installation is a one-time cost not considered in these estimates.

How much does supplemental (or secondary) disinfection cost?

Supplemental (or secondary) disinfection costs $36,000 to $75,000 and up per year.

That’s the full annual cost for supplemental (or secondary) disinfection systems. It includes rental of the equipment, maintenance visits, replacement parts, system design engineering, water testing, and support. The exact price depends on your facility’s size, complexity, water chemistry, and the disinfection method used. Call Legionella Control Systems for an engineering site investigation, where an ASSE 12080 engineer will come to your facility, take a deep dive into your water chemistry and facility’s needs, and then give you the best options. Installation is not included in this figure and is bid separately based on your specific site.

What does the $36k-$75k annual cost actually cover?

This cost includes everything except hooking the supplemental disinfection system up.

Your supplemental disinfection system cost includes the equipment, regular maintenance calls to keep it running, replacement parts when they wear out, engineering design to match your water system, system optimization as your water conditions change, and ongoing testing and documentation. You’re not just renting one-size-fits-all equipment. You’re getting a system designed and optimized by engineering experts.

What affects the cost of a supplemental disinfection system?

Factors that affect the cost are the facility size, complexity, the disinfection method, and your water conditions.

A small hotel with a single hot water loop costs less than a hospital with multiple zones, cooling towers, and distributed branch lines. A system using a mixed oxidant solution may have a different cost than chlorine dioxide of CSI. Water hardness, pH, conductivity, and your baseline disinfectant residual all factor in. Your facility’s footprint, plumbing design, and mechanical systems determine how the water moves through your building, and all these factors affect the best solutions for your unique facility.

What disinfection methods does Legionella Control Systems use?

Legionella control systems disinfection offers disinfection methods that include mixed oxidant solution (MOS), copper-silver ionization (CSI), chlorine dioxide, and monochloramines.

Legionella Control Method	Key Benefits	Important Considerations
Mixed Oxidant Systems	Effective against Legionella and other waterborne pathogens.	Requires proper equipment selection, monitoring, and maintenance based on the facility’s water system.
Copper-Silver Ionization	Uses ionized copper and silver to help prevent Legionella growth. It produces no disinfection byproducts and lasts the longest in the water.	Effectiveness depends on water chemistry, system design, and proper ion level monitoring.
Chlorine Dioxide	Provides strong residual protection throughout the water system.	Requires careful monitoring and control to maintain effective treatment levels.
Monochloramine	Maintains residual protection in the distribution system longer than some other methods.	Requires evaluation of water chemistry, building layout, and compatibility with the facility’s plumbing system.

Your facility is unique, and each Legionella control method has different equipment requirements, maintenance needs, and effectiveness profiles. After an engineering site investigation, our engineers will evaluate your water chemistry, building layout, and operational needs to recommend the most cost-effective approach for your situation.

Why is this a yearly cost and not a one-time purchase?

Because doing this right is the difference between life and death.

Supplemental disinfection isn’t a set-it-and-forget-it solution. If these systems are not maintained correctly, Legionella and biofilm grow back. A single outbreak can kill people, shut down your facility, trigger lawsuits, destroy your reputation, and cost millions in remediation and liability. Healthcare facilities have faced wrongful death claims. Hotels have had to close for months. The annual cost of ongoing maintenance and monitoring is the insurance you buy against catastrophic risk. Skipping it to save money isn’t cost control, it’s gambling with lives.

What if my facility is really large?

Costs scale, and we build custom solutions for complex systems.

A university campus or healthcare complex with multiple buildings may run $75,000 to well over $100,000 per year, depending on the number of treatment points and frequency of maintenance required. At Legionella Control Systems, we assess your actual water system, not just square footage, and we build a solution that makes sense for your specific layout and risk profile. These larger facilities often benefit from more sophisticated monitoring and optimization that we include in the engagement.

What happens if the supplemental disinfection system is not maintained properly?

Legionella can come back, and you could face liability and health risks.

Skipping maintenance to save money defeats the purpose. Disinfectant residuals drop, biofilm grows back, and Legionella finds a home again. That’s when you end up needing emergency remediation, which costs far more than preventive maintenance. We help you understand why the maintenance schedule matters and the consequences if you slip.

Can I stop supplemental disinfection once I start?

You can, but you need a replacement strategy.

If you decide a certain supplemental disinfection program isn’t right for your facility, you’ll need to implement other control measures to control Legionella. At LCS, we offer all the major disinfection methods and can pivot depending on your needs. Your facility’s specific risk profile determines what works, but over time, the method you started with might not be optimal. Most facilities find that some sort of supplemental disinfection is a big part of the practical long-term solution because it maintains a protective residual throughout your piping system.

How do I know if supplemental disinfection is the right choice?

If you have stagnant water, low chlorine residuals, temperature ranges where Legionella thrives, or past positive cultures, it usually is.

If your hot water loops, or distributed branch lines, sit in the temperature danger zone (68°F to 122°F), if you have dead legs or areas with poor circulation, or if you’ve had a positive legionella test, supplemental disinfection is worth considering. We can do an engineering risk assessment and root cause analysis to tell you whether your facility actually needs it or whether simpler control measures like filtration, UV, or flushing might work.

Do you offer a trial period for secondary disinfection systems?

We can discuss pilot programs for larger facilities.

If you want to test supplemental disinfection on one zone or one building before committing to your whole facility or all of your buildings, we will work to prove system efficacy. Some hospitals and hotel chains run a pilot in one building to see results before rolling out system-wide. This helps you understand the real-world cost and effectiveness for a single facility.

How soon can you start?

Design and equipment procurement typically takes 4 to 6 weeks. Installation depends on your facility’s complexity.

Once you decide to move forward, we’ll get you a detailed scope, timeline, and pricing. The equipment doesn’t sit on a shelf waiting. We will order it for your specific system configuration. Installation work happens after that and is scheduled based on your operational needs and contractor availability.

Does Legionella Control Systems design and install these systems?

We design them, partner with your preferred installers, and manage the overall program.

We handle the engineering, sizing, water testing, and ongoing monitoring. Your general contractor or our recommended partners handle installation. We stay involved throughout to make sure the system is installed correctly and optimized once it’s running.

Do you provide documentation for compliance?

Yes. All designs, testing, and maintenance are documented to support your water management plan.

We provide ASSE 12080 certified engineers to review your system, testing reports, maintenance logs, and system optimization records. That paper trail protects you if you ever need to show regulators or attorneys what you’ve been doing to manage legionella risk. It’s part of a defensible water management program.

FAQ Costs of Supplemental Disinfection, including CSI, Mixed Oxidants, Chlorine Dioxide, and Monochloramines

What is included in the $36k-$75k annual cost for supplemental disinfection?

The annual cost includes equipment rental, maintenance visits, replacement parts, engineering design, system optimization, water testing, and ongoing support. Installation is a separate cost.

What supplemental disinfection systems are the most common?

Mixed oxidant solution (MOS), copper-silver ionization (CSI), chlorine dioxide, and monochloramines are the most common modalities for water disinfection in the United States. We offer all these systems and can customize them to your needs.

If I have supplemental disinfection, is there an advantage to adding a point of entry (POE) filtration or UV disinfection?

Yes! A multi-barrier approach will yield the best results. Mixed oxidant solution (MOS), copper-silver ionization (CSI), chlorine dioxide, and monochloramines will all work more efficiently if sediment and bacteria are reduced. It will have less work to do and be more effective. And certain pathogens like Mycobacteria (NTM) are very hard to kill with disinfectants, but are easily handled with UV or filtration. The combination is a potent strategy for reducing all pathogens.

Is Installation included in the $36k-$75k annual cost for supplemental disinfection?

Installation is not included in the $36,000 – $75,000 annual cost. Though we don’t do installations internally, we will work with you and the contractor to make sure all the equipment has been installed correctly.

Why does supplemental disinfection cost so much?

The $36,000 – $75,000 doesn’t compare to the millions of dollars that your facility will have to pay for if you have a Legionnaires outbreak. These costs can be over a million dollars per infected patient or customer. And you’re not just paying for equipment. You’re paying for active management of your water system. That means regular maintenance, parts replacement, chemistry adjustments, engineering expertise, and testing to make sure the system stays effective.

How much does a Legionnaires’ outbreak cost?

Costs range from $100,000s to $1,000,000s, depending on the circumstances. You can go to our Legionnaires Outbreak Cost Calculator to estimate how much an outbreak might cost your facility.

What if I can’t afford supplemental disinfection?

Explore other control methods like point of entry (POE) and hot water loop filtration and UV disinfection systems paired with aggressive flushing. We’ll help you evaluate what makes sense for your budget and risk profile. Sometimes a combination of simpler measures works. Doing nothing is not an option if you have Legionella risk.

Can I install supplemental disinfection myself or use a cheaper vendor?

You can, but you need someone who understands water chemistry, system design, and Legionella risk. Cutting corners often leads to ineffective residuals, repeated failures, and emergency remediation costs that are much higher. Choose a vendor with a degree in mechanical or chemical engineering who possesses an ASSE 12080 certification.

How long does supplemental disinfection take to work?

That depends on your baseline conditions and the disinfection method chosen. It also depends on the state of your plumbing system and if you have filtration and UV disinfection in place. If your water is heavily contaminated with biofilm, it can take weeks or months to clean it out completely. If you’re starting preventively, or if you have POE and hot water loop filtration, results are considerably faster. We will monitor your water and tell you when you’ve reached your target Legionella control threshold.

Will supplemental disinfection affect my water quality or taste?

It depends on the method. Copper-silver ionization has minimal taste or odor impact and doesn’t leave a chemical residual. Chlorine dioxide, mixed oxidant and monochloramine can leave slight taste characteristics but often there is no noticeable difference.

What if my facility shuts down temporarily?

Your water system doesn’t stop just because you’re not fully occupied. Legionella will grow in dormant systems. We help you plan a maintenance protocol for shutdowns and restarts to keep the system safe during periods of reduced operation.

Do you offer a guarantee on legionella control?

We can’t guarantee Legionella will never grow anywhere in your system. Our goal is to minimize the risk of Legionella and Legionnaires ‘ disease. What we guarantee is that we’ll design and manage a system using current best practices that significantly reduces your risk. Regular validation testing confirms whether it’s working.

How often will someone visit my facility?

That depends on your system and contract. Site visits vary from weeks to months, depending on your facility. Your specific system design and maintenance plan determines the schedule. We build that into our proposal upfront.

Can you integrate Chlorine Dioxide, Mixed Oxidants, CSI, or Chlorine Dioxide disinfection systems with my existing water management program?

Absolutely. Supplemental disinfection is one piece of your overall water management plan. We coordinate with your current testing, flushing protocols, and facility operations.

Have questions about supplemental disinfection costs for your facility?

Get in touch with one of our engineers to discuss your specific situation and drill down on the best supplemental/secondary disinfection system and find out the exact costs.