Legionella Water Treatment

Legionella water treatment is one of the most critical steps you can take to protect people in and around your facility from a preventable, potentially deadly disease. If you operate industrial or commercial water systems—such as cooling towers, process water, or complex building plumbing—our team at Fact Water Co. can design and manage a Legionella water treatment program tailored to your operation so you stay safe, compliant, and confident.

What is Legionella and why it matters

Legionella is a naturally occurring waterborne bacteria that can multiply inside man-made water systems when conditions allow. When water containing Legionella becomes aerosolized—from cooling towers, showers, faucets, or decorative water features—people can inhale tiny droplets and develop Legionnaires’ disease, a severe form of pneumonia. Industrial and large commercial facilities are at particular risk because they often rely on extensive piping, storage tanks, and recirculating loops that can create warm, stagnant zones where bacteria thrive.

ASHRAE 188 and standard compliance

• ASHRAE 188 is a standard created in 2015 (and updated in 2018) which outlines the importance of a water management plan for preventing the growth and spread of Legionella, a bacteria that can lead to the potentially life-threatening Legionnaires Disease. The standard suggests that certain facilities like healthcare facilities or overnight facilities (such as hotels) actively treat water for Legionella. While this is an optional standard, many local building codes are requiring facilities to adhere to it and create a new water treatment plan or update an existing one.

How Legionella grows in industrial water systems

Legionella prefers warm water, typically between 77–113°F (25–45°C), especially where disinfectant levels are low and biofilm is present. Common problem areas in industrial and commercial environments include:

• Cooling towers and evaporative condensers used in HVAC and process cooling.
• Large potable hot water systems, storage tanks, and recirculating loops.
• Complex plumbing with dead legs, low-flow fixtures, and underused branches.
• Industrial process water systems with warm temperatures and nutrients.

Biofilm on pipe and equipment surfaces protects Legionella from disinfectants and provides nutrients, so any effective Legionella water treatment approach must address both free-floating bacteria and biofilm.

Core elements of Legionella water treatment

Effective Legionella water treatment is not a single product or one-time “shock”; it is an integrated, ongoing program that combines engineering controls, chemistry, and monitoring.

Key elements include:

• Temperature management: Maintain hot water above about 140°F (60°C) at heaters and keep cold water below 68°F (20°C) wherever feasible, while following local anti-scald regulations.
• Disinfection and biocides: Use oxidizing biocides (such as chlorine, chlorine dioxide, or bromine) and, where appropriate, non‑oxidizing biocides to control microbial growth and maintain a protective residual throughout the system.
• Biofilm and scale control: Apply chemical programs that limit scale and corrosion, and incorporate dispersants or biodispersants to disrupt biofilm so disinfectants can work effectively.
• Filtration and solids management: Use side‑stream filtration or ultrafiltration on cooling and process water to remove suspended solids and bacteria that can harbor Legionella.
• System design and maintenance: Eliminate dead legs, maintain recirculation, clean and disinfect tanks and cooling towers regularly, and follow documented procedures for startup, idling, and shutdown.

In many facilities, automated feed and control systems help maintain stable water chemistry, reduce human error, and support continuous Legionella water treatment across varying loads and operating conditions.

Legionella control in cooling towers and industrial equipment

Fact Water Co. focuses on practical, facility-specific solutions rather than generic recommendations. As an industrial water treatment provider, we bring hands-on experience with chemistry, equipment, and daily operations, so our consulting deliverables are designed to be implemented—not just read.

You also benefit from:

• A facts-first culture that emphasizes data, testing, and clear communication.
• Experience across a range of industries and system types, from process water to complex industrial wastewater.
• The ability to support everything from quick troubleshooting engagements to full A-to-Z guidance on new or upgraded systems.

If your business depends on reliable water and wastewater systems, specialized industrial water treatment consulting is one of the most effective ways to protect that reliability.

Fact Water Co. does not provide consulting services for residential systems, which allows us to stay focused on the specific demands of industrial and commercial facilities. Every engagement is built around the realities of production schedules, safety requirements, and regulatory oversight that industrial operations face daily.

Example table: key Legionella water treatment levers

Water management programs and regulatory confidence

Global public health agencies recommend formal water management programs (WMPs) to control Legionella risk in building and industrial water systems. A robust WMP typically includes:

• A multidisciplinary team responsible for water safety and Legionella water treatment.
• A detailed description of all water systems and identification of areas where Legionella could grow and spread.
• Control measures with defined setpoints, monitoring methods, and corrective actions.
• Recordkeeping, verification, and, where appropriate, validation through Legionella testing.

For industrial operators, a documented Legionella water treatment program supports compliance with OSHA expectations, accreditation requirements in healthcare and similar environments, and state or local water management regulations.

How Fact Water Co. supports Legionella water treatment

At Fact Water Co., we focus on industrial and commercial water systems, helping facilities translate public health guidance into practical, site‑specific Legionella water treatment programs. Our engineers and water treatment specialists can:

• Assess your existing cooling towers, process water, and building water systems for Legionella risk and operational constraints.
• Design chemical treatment, filtration, and monitoring packages that integrate with your existing infrastructure and automation.
• Develop and maintain written procedures for routine operation, cleaning, disinfection, and emergency response after a positive Legionella result.
• Support training, documentation, and communication so your team understands both the “why” and the “how” behind your Legionella water treatment plan.

If you are responsible for cooling towers, industrial water systems, or large commercial plumbing, now is the time to review your Legionella water treatment strategy—not after an outbreak, inspection finding, or unplanned shutdown. Contact Fact Water Co. today to speak with a Legionella water treatment specialist and start building a safer, more resilient water system around your facility.