Legionella prevention in U.S. facilities: Plumbers & installers on the front line

Legionella prevention has become a top priority in U.S. facilities, as reported cases of Legionnaires’ disease have continued to rise since 2000. Most outbreaks are linked to building water systems such as showers, faucets, and cooling towers, everyday fixtures that can quietly harbor bacterial growth.

In plumbing systems, the risk rises with stagnant water, warm temperatures (68°F–122°F), and buildup of biofilm or scale. Even when municipal water enters a facility clean, Legionella can multiply within internal plumbing networks if systems aren’t properly designed, maintained, or filtered.

Legionella prevention for plumbers and installers is essential at every stage, from system design and installation to ongoing service and replacement, as it’s key to protecting public health, client trust, and professional reputation.

Where are Legionella risks highest in U.S. facilities?

Legionnaires’ disease outbreaks aren’t associated with one sector; they’ve been found across a wide range of facilities throughout the U.S.

A study published in the CDC’s MMWR found that Legionnaires’ disease outbreaks occurred in diverse building types, showing how no water system is immune to risk.

Hotels and resorts (44%), long-term care facilities (19%), hospitals (15%), senior living facilities (7%), workplaces (7%), and community settings (7%).

These findings reveal that both hospitality and healthcare facilities, where water use is extensive and occupants may be more vulnerable, are especially high-risk. It is also identified that the most frequent sources of exposure are potable water, which includes all water used for drinking, handwashing, showering, and food preparation.

For plumbers and installers, this is a critical insight that ordinary plumbing systems can quickly become a primary transmission route if not protected.

How plumbers & installers can prevent Legionella in building water systems?

Legionella prevention starts with smart system design and certified installation practices. Plumbers and installers play a frontline role in ensuring that water systems stay compliant, efficient, and safe.

Maintain proper water temperatures

Maintain hot water at ≥60°C (140°F) and deliver at ≥50°C (122°F); keep cold water below 20°C (68°F) and design plumbing to prevent cooling or stagnation that promotes bacterial growth.

Reduce stagnation

Remove dead legs and unused pipe runs, install automatic flushing in low-use areas, and design plumbing systems to maintain continuous water movement, reducing stagnation and the risk of bacterial growth.

Use certified point of entry and point-of-use filtration

Make use of certified point-of-entry (POE) and point-of-use (POU) filtration systems to create multiple barriers against waterborne bacteria. MWT’s certified filters help ensure consistent water quality, protect high-risk outlets, and support overall Legionella prevention efforts.

Follow ASHRAE guideline 12 standards 188 & 514

Adhere to ASHRAE 188 and local codes by implementing a Legionella Water Management Plan (WMP). For healthcare, reference ASHRAE Guideline 12 and CDC Legionella Toolkit, ensuring all installations use EPA, NSF, ASSE, or ASTM-certified filtration for compliance and safety.

MWT filters are engineered to meet these standards, featuring 0.08 µm hollow-fiber membranes that reduce bacteria and fungi, achieving Log 8 (99.999999%) reduction. 

Each filter is produced in an EPA FIFRA-registered establishment (No. 105402-NLD-1) and independently tested to ASTM F838-2020, NSF/ANSI, and ASSE 2011-2022 certifications for verified performance and reliability.

Certified ultrafiltration solutions, delivered direct to plumbers & installers

While thermal disinfection and chemical treatments can help reduce bacteria, they often fail to reach biofilm-protected zones inside pipes. Ultrafiltration provides a reliable physical barrier, consistently reducing pathogens before they reach the outlet, ensuring safer water at every point of use.

On MWT-Direct, get certified, professional-grade filtration systems, direct to plumbers & installers with no minimum order requirements and fast U.S. delivery.

Shop trusted Legionella prevention solutions today on MWT-Direct: https://www.mwt-direct.com