Legionella Risk Assessment, Legionnaires’ Disease Site Investigation, and Root Cause Analysis: Pricing and What to Expect

Get a clear picture of what a Legionella risk assessment or engineering site investigation involves and what the core tools for preventing and responding to Legionnaires’ disease will cost your facility. The sections below detail pricing, what is included, what affects the cost, and what to expect from the assessment or investigation.

Legionella Control Systems conducts proactive risk assessments, reactive site investigations, and root cause analyses for hospitals, long-term care facilities, hotels, correctional facilities, condo associations, and large commercial and manufacturing buildings nationwide. Assessments are conducted by ASSE 12080 certified engineers and include a written report with findings, test results, and prioritized short, medium, and long-term recommendations.

How much does a Legionella risk assessment or engineering site investigation cost?

A Legionella risk assessment or engineering site visit costs between $4,900 and $12,000 per building.

That range covers proactive risk assessments, reactive site investigations following positive Legionella tests, and full root cause analyses during active outbreak investigations. Price depends on building size, water system complexity, the number of hot water loops and floors, and whether the work involves a health department. All onsite water quality field testing, including pH, free chlorine, temperature, ORP, conductivity, hardness, and pressure, is included in the per-building fee. Legionella cultures or other microbiological testing are billed separately.

What is the difference between a Legionella risk assessment and an engineering site investigation?

A risk assessment is proactive. An engineering site investigation is reactive.

A proactive Legionella risk assessment is conducted before anyone is sick: it identifies conditions that could support Legionella growth and gives you a prioritized action plan. An engineering site investigation is reactive, triggered by a positive Legionella test, multiple positives, or a confirmed or suspected case of Legionnaires’ disease. When two or more cases are linked to a facility, health departments open a formal case investigation, and your facility needs an independent engineering subject matter expert to identify the source and document corrective actions.

What affects the price within that range?

Building size, water system complexity, hot water loops, floors, and health department involvement.

A single-story long-term care facility with one hot water loop is straightforward. A multi-story hospital with multiple hot water zones, cooling towers, branch lines, storage tanks, and point of use fixtures across hundreds of rooms is far more involved. The number of locations that must be walked, tested, and documented drives time and price, and a health department case investigation adds coordination. Most investigations fall within $12,000 per building.

What does the investigation actually cover?

A full water-system review, onsite field testing, and a written report with recommendations.

The investigation covers your hot and cold water systems, water heaters and storage tanks, softeners, piping, dead legs, and areas of stagnation. We identify locations for bacterial testing if needed and take the onsite water quality measurements listed above. You receive a written report with all findings, field test results, and prioritized immediate, midterm, and long-term recommendations, plus water management plan guidance. The goal is to tell you what your facility actually needs, not to sell the most expensive solution.

Is Legionella culture testing included in the price?

Onsite field water quality testing is included. Legionella cultures and microbiological testing are billed separately.

The per-building fee covers all onsite field measurements the engineer conducts. If the investigation reveals locations that warrant Legionella culture testing or other microbiological sampling, that testing is quoted and billed separately. We always tell you before any additional testing is ordered and explain why it is warranted.

The health department is asking us to remediate. Do we have to start there, or can we do the assessment first?

Do the assessment first. Health departments nearly always agree, and it is the right call.

Remediating without understanding the root cause is like treating a symptom without a diagnosis: you may spend $25,000 to $100,000 on the wrong solution and still have Legionella growing. A proper engineering site investigation identifies where the organism is living, why it is there, and what will get rid of it. Health departments understand this and nearly always allow the assessment before remediation. Engaging an independent ASSE 12080 certified engineer also signals to regulators that your facility is acting in good faith.

What happens when the health department is involved?

When two or more cases are linked, a formal case investigation opens. Your facility needs an independent engineering subject matter expert.

A single confirmed case of Legionnaires’ disease is serious. When two or more cases are linked to the same facility, health departments open a formal case investigation, and you are managing a regulatory and legal situation, not just a water quality issue. Legionella Control Systems works alongside investigators, documents findings independently, and provides the technical expertise your facility needs. Engaging an independent ASSE 12080 certified engineer from the start is critical.

Who conducts the assessment?

An ASSE 12080 certified mechanical engineer with deep experience in waterborne pathogen control.

ASSE 12080 is the industry standard for Legionella water safety and management. Our engineers hold that certification and bring a mechanical engineering foundation and decades of experience in water systems. Understanding plumbing design, fluid dynamics, heat transfer, and water chemistry separates a meaningful risk assessment from a checklist exercise. We interpret what we find in the context of how your system actually operates.

Which types of facilities do you serve?

Hospitals, long-term care, hotels, correctional facilities, condo associations, and large commercial and manufacturing buildings, nationwide.

Any facility with a centralized water system and a vulnerable population has Legionella risk. Healthcare and long-term care face the highest scrutiny and most vulnerable populations; hotels carry liability from cooling towers, decorative fountains, and large hot water systems; correctional facilities face the same risks with fewer resources; condo associations and commercial buildings often have aging infrastructure never designed with Legionella in mind. We also work with consulting engineers, and conduct assessments anywhere in the United States.

Does Legionella Control Systems do anything beyond the assessment?

Yes. We are a full-service Legionella control firm.

The assessment is often the starting point. Depending on what we find, we help with Legionella remediation, secondary disinfection including chlorine dioxide, monochloramine, mixed oxidants, and copper-silver ionization, water management plan development, testing and sampling, point of use filtration, and ongoing engineering support. We are not a lab that hands you a number and walks away; we help you understand what the results mean and what to do.

Do you have questions about your facility’s needs?

Call 888-416-8626 or get in touch with our team to discuss your situation.

FAQ: Legionella Risk Assessment and Engineering Site Investigation Pricing

How much does a Legionella risk assessment cost?

Risk assessments start at $4,900 per building; full engineering site investigations and root cause analyses run $4,900 to $12,000, depending on building size, water system complexity, and health department coordination.

What is included in the per-building fee?

The onsite investigation, a full water-system review, field testing (pH, free chlorine, ORP, conductivity, hardness, temperature, pressure), and a written report with prioritized recommendations. Legionella cultures are billed separately.

Is Legionella testing included in the price?

Onsite field water quality measurements are included; Legionella culture and microbiological testing are billed separately, and we explain why before ordering.

What is the difference between a risk assessment and a root cause analysis?

A risk assessment is proactive, identifying conditions that could support Legionella growth before anyone gets sick. Root cause analysis is reactive and forensic, conducted after detection or illness to identify where and why the organism is growing.

What drives the price toward $12,000?

Larger buildings with more floors, hot water loops, cooling towers, storage tanks, and branch lines take more time, and health department coordination during an active case investigation adds work.

Does travel cost extra?

Scope and travel are discussed during the initial consultation. We conduct assessments anywhere in the United States and build a proposal specific to your facility.

What do we get at the end of the assessment?

A written report with current risk factors, all findings, field test results, and prioritized immediate, midterm, and long-term recommendations, plus water management plan guidance.

Who reviews and conducts the assessment?

An ASSE 12080 certified mechanical engineer with direct experience in Legionella control and waterborne pathogen management, the industry standard certification for Legionella water safety.

The health department is telling us to remediate. Can we do the assessment first?

Yes, and you should. Health departments nearly always allow an engineering site investigation before remediation because it leads to better outcomes. Remediating without a root cause analysis risks spending $25,000 to $100,000 on the wrong fix.

What happens if the health department is already involved at our facility?

Call us immediately. When two or more Legionnaires’ cases are linked to a facility, a formal case investigation opens, and you need an independent engineering expert engaged from the start.

Do you only do assessments, or can you help us fix the problem?

We are a full-service Legionella control firm. Beyond the assessment: remediation, secondary disinfection, water management plans, testing and sampling, point of use (POU) and point of entry (POE) filtration, UV disinfection, and ongoing engineering support.

Which industries do you serve?

Hospitals and health systems, long-term care and skilled nursing, hotels, correctional facilities, condo associations, large commercial buildings, manufacturing, and consulting engineering firms, anywhere in the United States.

Contact Us

We can help with your Legionella risk assessment, Legionella testing, Legionella remediation, secondary disinfection, and everything else you need to control Legionella. Contact the Legionella experts at [email protected] or 888-416-8626.