Legionella Risks in Summer: Why Warm Weather Increases the Threat
When we think of summer, we picture sunshine, holidays, and warm evenings. But with the rising temperatures comes an often-overlooked health concern: Legionella.
This bacteria can thrive in certain water systems, and warm weather creates ideal conditions for growth. That’s why understanding why warm weather increases the threat is vital—especially for employers and duty holders.
In this blog, we’ll explain the summer risks clearly and offer helpful tips to keep your workplace safe.
What Is Legionella and Why Should You Care?
Legionella is a type of bacteria that can cause Legionnaires’ disease, a serious lung infection.
It lives in water and multiplies when temperatures sit between 20°C and 45°C. That’s why warmer months create the perfect environment for Legionella to thrive.
Even small water systems—like taps, showers, and fountains—can be at risk. If these are left unused or poorly maintained, the danger rises.
Why Warm Weather Increases the Threat
In summer, stored water can quickly warm up, especially in underused outlets. For example, during school holidays or reduced office hours, water sits still and heats up.
This stagnant, warm water creates ideal conditions for Legionella to grow.
And once airborne, through spray or mist, it becomes a health risk—particularly in workplaces where people are exposed regularly.
That’s why employer duties must adapt during summer to manage these changing risks.
Your Legal Duty as an Employer
Under the Health and Safety at Work Act and COSHH regulations, every employer has a duty to protect their staff from harm.
That includes managing Legionella risk assessments and making sure water systems are kept safe, especially in warmer months.
Ignoring this could lead to serious illness, damage to your business reputation, or legal consequences.
Key Tips to Reduce Legionella Risk This Summer
Here are a few simple, effective tips to help stay ahead:
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Flush infrequently used outlets weekly. Especially during holiday closures or reduced staffing.
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Monitor water temperatures regularly. Keep cold water below 20°C and hot water above 50°C.
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Review your Legionella risk assessments. Make sure they reflect current building use and summer conditions.
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Keep records. Record flushing, temperature checks, and inspections—this shows you’ve met your legal duties.
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Seek expert help if unsure. A professional can advise you on controls specific to your site.
Supporting Safer Workplaces This Summer
Managing Legionella is not just a legal requirement—it’s part of good workplace safety.
With temperatures rising, employers must remain alert. Risks can change with the seasons, and your controls should change too.
By updating your Legionella risk assessments, flushing outlets, and staying informed, you help keep everyone safe.
Need Support? We’re Here to Help
At OJ Health & Safety, we support businesses like yours with clear, reliable guidance. Whether you need a review, an assessment, or just honest advice, we’re here to help.
Let us take the stress out of compliance, so you can focus on running your business.
Warm weather may increase the threat, but together, we can reduce the risk.