Legionnaires' Disease & Ventilation — May 2024

In May 2024 we published a focused guide on how proper ventilation helps prevent Legionnaires' disease. That post breaks down why air and water systems matter, where bacteria hide, and what simple steps building owners and homeowners can take right now.

Legionella grows in warm, stagnant water and spreads when contaminated water droplets reach a person’s lungs. Most people know Legionnaires' disease is linked to cooling towers and hot tubs, but HVAC and plumbing systems inside buildings also play a big role. Good ventilation reduces the chance that infected aerosols will reach people and helps keep systems dry and clean.

Quick takeaways from our post

First, ventilation alone won’t stop Legionella if water systems are neglected. Second, increasing fresh air, fixing leaks, and removing moisture cuts risk fast. Third, regular maintenance and water testing are non-negotiable for public buildings, hotels, and health facilities. These are the core points we emphasized in May.

Practical steps you can use today

Check where water can sit and warm up. Look at cooling towers, decorative fountains, hot water tanks, and rarely used taps. Flush unused outlets weekly and keep hot water at safe temperatures above 50°C (122°F) where possible to limit growth. If you manage a building, document flushing and maintenance so you can show compliance.

Improve air flow. Open windows when weather and security allow, and increase fresh air settings on HVAC systems. Use well-maintained exhaust fans in bathrooms and kitchens to cut humidity. Consider upgrading filters to MERV 13 or higher if your HVAC can handle them; filters don’t stop Legionella in water, but they improve overall air quality and reduce other airborne risks.

Keep an eye on cooling towers and evaporative condensers. These are high-risk sources. Schedule professional cleaning, biocide treatment, and inspection at recommended intervals. If you see scale, rust, or slime, act fast. Certified water treatment companies can test for Legionella, advise on chemical controls, and help write a water safety plan.

For small businesses and homeowners, simple habits help a lot. Run taps and showers after long closures, clean showerheads monthly, and remove devices that create fine mist if you can’t confirm their maintenance. If you’re renovating, avoid complex water systems that you won’t be prepared to maintain.

Test water systems annually and after big changes; test quarterly in hospitals and care homes. For example, a hotel reopening after closure must test before welcoming guests and record the results.

If you find a suspected case of Legionnaires' disease, act quickly. Contact public health authorities and a qualified water treatment firm. They will guide testing, remediation, and communication steps to protect occupants and staff. Transparency matters: telling users about investigations and temporary closures builds trust and reduces further exposure.

Our May article gives step-by-step checklists and explains why each measure works. If your priority is safer indoor air and water systems, start with a simple inspection, schedule HVAC and plumbing maintenance, and set up routine water flushing. Small, regular actions prevent big outbreaks.