What is Legionella and why should landlords care?

Between managing gas safety certificates, EICRs, and keeping up with the Renters' Rights Act, water safety obligations can sometimes slip through the cracks. Yet understanding Legionella risks and your responsibilities around them is just as important as any other compliance requirement. This article breaks down everything you need to know about Legionella risk assessments, from the legal framework to practical control measures.

Understanding your water safety obligations as a landlord

Legionella is bacteria that naturally occurs in water but can become dangerous when it multiplies in man made water systems. When people inhale small droplets of water contaminated with Legionella bacteria, they can develop Legionnaires' disease, a severe and potentially fatal form of pneumonia.

The symptoms typically last between two to ten days and resemble severe flu, including:

• High fever

• Cough

• Shortness of breath

• Muscle aches, and

• Headaches.

While treatable with antibiotics if caught early, Legionnaires' disease can be fatal in approximately 10-15% of cases, particularly for vulnerable individuals.

Certain groups face higher risks from Legionella exposure. Older people, those with existing lung conditions, individuals with weakened immune systems, and heavy smokers are all more susceptible to developing serious illness if exposed to the bacteria.

Legionella thrives in specific conditions. The bacteria multiplies rapidly in water temperatures between 20°C and 45°C, which is why proper temperature control is critical. It also flourishes in stagnant water where it has time to colonise, and in systems with rust, scale, or other debris that provide nutrients for bacterial growth.

The legal framework: what the law actually requires

Your obligations around Legionella stem from several pieces of legislation that work together to create a clear duty of care.

Under Section 3(2) of the Health and Safety at Work Act 1974 (HSWA), landlords are classified as self-employed individuals. This means you have legal responsibilities to ensure your rental property is managed in a way that doesn't expose tenants to health and safety risks.

The Control of Substances Hazardous to Health Regulations 2002 (COSHH) provides the framework for managing risks from hazardous substances, including biological agents like Legionella. Under COSHH, you must identify potential risks and implement necessary control measures.

The Approved Code of Practice L8, titled "Legionnaires' disease: The control of legionella bacteria in water systems," offers practical guidance on meeting these requirements. Published by the Health and Safety Executive (HSE), it clarifies what landlords need to do in proportionate, practical terms.

Here's what's important to understand. Whilst you have a legal duty to assess and control Legionella risks, you are not required to obtain a formal "Legionella test certificate." This is a common misconception that some consultants and letting agents have unfortunately exploited.

The HSE is clear on this point. Testing or sampling water for Legionella is generally not required for domestic hot and cold water systems and is only necessary in exceptional circumstances. What you do need is a risk assessment carried out by someone competent, which could be you or a professional you hire.

Who needs to conduct a Legionella risk assessment?

This requirement applies broadly. Whether you rent out an entire property, a single room within your home, or manage a property portfolio of HMO properties, you fall under these regulations if you provide accommodation under a lease or licence shorter than seven years.

The duty applies to all types of landlords, from private individuals renting out a spare room to housing associations managing hundreds of units. If you're providing residential accommodation for rent, you have a legal obligation to address Legionella risks.

Can you conduct the assessment yourself?

Yes, in most cases you can carry out your own Legionella risk assessment, and many landlords do exactly that for standard domestic properties.

The HSE describes a competent person as someone with sufficient training, experience, knowledge, or other qualities to properly assist you. For a typical house or flat with straightforward water systems, this doesn't necessarily require professional qualifications.

However, you need to understand what you're assessing. This means knowing how Legionella grows, recognising risk factors in water systems, understanding appropriate control measures, and being able to document your findings properly.

Most landlords can develop this competence through research and the use of proper assessment templates. The HSE provides free guidance, and organisations like the NRLA offer risk assessment forms to members.

That said, professional assessments make sense in certain situations. If your property has complex water systems, multiple storage tanks, or commercial grade equipment, a professional assessor brings valuable expertise. Properties with a history of water quality issues or those that have stood vacant for extended periods may also benefit from professional assessment.

Professional assessors typically charge between £75 and £200 for a standard domestic property, with the inspection taking 20 minutes to an hour depending on property size. They'll take digital temperature readings at every hot and cold tap, inspect all taps and showerheads visually, identify redundant pipework, and check exterior taps and hoses.

What a Legionella risk assessment involves

A thorough legionella risk assessment follows a systematic approach that examines your property's water systems comprehensively.

Start by identifying all water systems in your property. This includes your:

• Domestic hot and cold water supply

• Water storage tanks - including cold water tanks in lofts and hot water cylinders

• All taps and outlets throughout the property

• Showerheads and hoses, and

• Any other water-using appliances or features.

Next, assess the actual risks present. Look at water temperature throughout the system, considering whether hot water reaches and maintains 60°C at the cylinder, if cold water stays below 20°C, and whether any areas allow water to sit in the danger zone of 20-45°C.

Examine water flow and usage patterns. Properties left vacant, seasonally occupied student accommodation, or rarely used guest facilities in short term lets all present higher risks due to potential stagnation.

Check the physical condition of your water systems. Look for rust, scale, or biofilm in tanks and pipes, redundant or dead leg pipework where water sits unused, damaged or missing tank lids, and poorly insulated pipes that might allow temperature fluctuations.

Consider who might be at risk. While your standard tenancy agreement likely covers general adults, think about whether elderly people, individuals with health conditions, or those with weakened immune systems might occupy the property.

Evaluate how water droplets might become airborne. Showers are the primary concern as they create the aerosols that people can inhale, but also consider spa baths, humidifiers, or water features if present.

Based on your findings, implement control measures. These might include adjusting temperature settings, removing unused pipework, improving insulation, repairing or replacing damaged components, and establishing flushing regimes for little used outlets.

Document everything thoroughly and store these documents in the document feature of your landlord software. Record what you found, what you've done about it, when you'll review it again, and any ongoing maintenance required.

Essential control measures every landlord should implement

Prevention is far better than cure when it comes to Legionella, and several straightforward control measures dramatically reduce risk.

Temperature control forms your first line of defence. Hot water should be stored at 60°C at the cylinder and reach taps at a minimum of 50°C. Cold water should stay below 20°C, which usually means keeping cold water tanks properly insulated and located in cool spaces like lofts.

Before letting a property or after it's been vacant, flush the entire water system thoroughly. Run all taps, showers, and outlets for at least two minutes to clear any stagnant water. This simple step removes water that's been sitting in pipes where bacteria might have multiplied.

Keep water moving and systems in use. Weekly flushing of all outlets prevents stagnation. If you know a property will be vacant, for example between holiday lets, student properties during breaks, or void periods between tenancies, arrange for someone to flush the system weekly.

Maintain physical system integrity. Ensure all cold water tanks have tight fitting lids to prevent debris entering the system. Remove any redundant pipework where water can sit unused. Keep tanks, pipes, and fittings in good condition without rust, scale, or damage.

Shower heads require particular attention as they create the aerosols that present the highest risk. Clean and descale them regularly, at least quarterly. Consider replacing them annually as part of your maintenance schedule.

Consider equipment choices during refurbishment or installation. Combination boilers and electric showers reduce or eliminate water storage, substantially cutting Legionella risk. While not always practical to retrofit, keep this in mind for future upgrades.

Tenant communication and education

Your tenants play a crucial role in maintaining water safety, so clear communication becomes essential.

At move-in, explain basic water safety to your tenants as part of your onboarding process. Let them know not to adjust the hot water cylinder temperature, to use all taps and showers weekly, to clean showerheads regularly, and to inform you immediately if hot water isn't heating properly or if they notice any other system problems.

Make it clear that while you've assessed and controlled risks, ongoing use of the water system helps maintain safety. A property where taps and showers see daily use is inherently lower risk than one where some outlets sit unused for weeks.

Request that tenants inform you when the property will be vacant for extended periods. For student lets, holiday properties, or tenants who travel frequently, this allows you to arrange system flushing to prevent stagnation.

Document this communication properly. Include water safety information in your welcome pack, note it in your check-in report, and keep records of what you've told tenants and when.

How often should you review your assessment?

The law doesn't mandate specific review frequencies, but the HSE recommends reviewing Legionella risk assessments at least every two years for domestic properties, even low-risk ones.

However, certain circumstances demand earlier review. If you make significant changes to the property's water system, such as replacing the boiler, adding or removing water tanks, reconfiguring pipework, or installing new bathrooms, review your assessment.

New information about risks or control measures should also trigger a review. Perhaps you learn about Legionella issues in similar properties in your area, or new guidance emerges from the HSE or industry bodies.

If your monitoring reveals control measures aren't working as intended, review and revise your approach. For example, if temperature checks show water isn't reaching target temperatures, or if tenants report frequent problems, reassess.

Changes in property use can alter risk profiles. Converting a property to an HMO, changing from long-term to short-term lets, or any occupancy change affecting vulnerable people all warrant review.

Align reviews with your other compliance activities for efficiency. Many landlords review Legionella risks alongside annual gas safety inspections or during routine maintenance visits, using compliance tracking tools to stay organised.

Record keeping and documentation

Whilst landlords with fewer than five employees aren't legally required to keep written records, however maintaining comprehensive documentation is strongly advisable.

Good records demonstrate due diligence if ever questioned, as well as being the right thing to do. Should a tenant develop Legionnaires' disease, you'd need to prove you fulfilled your legal duty. Detailed records of assessments, control measures, and maintenance provide this evidence.

Record your initial risk assessment comprehensively. Document the date and who conducted it, description of all water systems examined, risks identified and their severity, control measures implemented, and review date planned.

Keep ongoing monitoring records. Track temperature checks at hot and cold outlets, system flushing dates when the property was vacant, maintenance carried out on water systems, and any issues identified and remedied.

Document tenant communications. Note when you explained water safety to new tenants, any reports from tenants about water system problems, and your responses to those reports.

Store these records systematically with all your other property documents. Modern property management platforms make this straightforward, keeping everything accessible and backed up securely.

Common myths and misconceptions

Several myths about Legionella requirements persist, often perpetuated by those trying to sell unnecessary services.

You do not need a "Legionella test certificate." This is perhaps the biggest misconception. Water sampling and laboratory testing are not legal requirements for domestic properties and are only needed in exceptional circumstances. Any company insisting you need testing and certification for a standard rental property is either misinformed or deliberately misleading you.

Professional assessments aren't mandatory for simple domestic properties. While beneficial in some cases, you can conduct your own assessment if competent.

The legislation hasn't recently changed, despite what some might claim. Requirements around Legionella risk assessment have been in place since 2001 when the L8 Approved Code of Practice was first published. The 2013 revision didn't introduce new obligations. It clarified existing ones.

Not all properties are high risk. Most standard domestic rental properties with straightforward water systems present relatively low Legionella risk when basic control measures are in place. Risk assessment helps you confirm this and implement appropriate precautions.

Annual assessments aren't mandatory. The two year review cycle recommended by the HSE is guidance, not law. Review when circumstances change, but don't feel pressured into annual reassessments unless your property's risk profile warrants it.

What happens if you don't comply?

The consequences of failing to address Legionella risks can be severe, extending well beyond administrative penalties.

While HSE and local authority inspectors don't proactively check domestic properties for Legionella risk assessments, serious consequences follow if a tenant contracts Legionnaires' disease.

You could face prosecution under the Health and Safety at Work Act. The HSE has authority to bring charges even if no one actually becomes ill, simply if they can prove tenants were exposed to risk. Fines for HSWA breaches are unlimited, and in severe cases, imprisonment is possible.

If someone becomes ill or dies from Legionnaires' disease traceable to your property, penalties escalate dramatically. You'd face potential criminal charges, unlimited fines, possible imprisonment, and civil liability for damages, medical costs, and suffering.

Beyond legal consequences, reputational damage can prove lasting. News of Legionnaires' disease cases spreads quickly, making it harder to let your properties and potentially affecting your entire portfolio.

Your insurance might not cover you if you've failed to conduct required risk assessments. Many policies require compliance with health and safety law as a condition of cover.

Integrating Legionella management into your compliance routine

The key to effective Legionella management is integration with your broader compliance activities rather than treating it as a separate, burdensome task.

Link assessments to other scheduled work. Conduct your initial Legionella risk assessment alongside your EICR or during property refurbishment before letting. Schedule reviews to coincide with annual gas safety checks or routine maintenance visits.

Build control measures into your standard procedures. Make system flushing part of your void property preparation. Include showerhead cleaning in your periodic inspection checklist. Set reminders for temperature checks during routine visits.

Use technology to stay organised. Modern property management software can store your risk assessments alongside other compliance documents, set automatic reminders for reviews, track when control measures were last checked, and flag properties approaching review dates.

Standardise your approach across your property portfolio. Create templates for assessments and store these in the document feature of your landlord app. Develop checklists for control measures. Build water safety into your standard tenant onboarding process.

For larger portfolios, prioritise properties based on risk. Properties with elderly tenants, complex water systems, or those frequently vacant might warrant more frequent attention than standard lets with simple systems and regular use.

Looking ahead: water safety and the Renters' Rights Act

The Renters' Rights Act coming into force in May 2026 brings enhanced enforcement and standards across the rental sector. Whilst it doesn't specifically change Legionella requirements, it creates a context where all compliance matters more.

The Act introduces the Decent Homes Standard to the private rented sector, strengthening property condition requirements. Whilst details are still emerging, comprehensive water safety management aligns with the spirit of these enhanced rental standards.

Expanded enforcement powers for local authorities mean councils can take stronger action on property standards. Landlords who neglect basic safety requirements, including water safety, may face increased scrutiny.

The new private rented sector ombudsman will handle tenant complaints about property conditions. Robust Legionella risk assessment and control provides evidence you're meeting your obligations if complaints arise.

Strengthen your compliance position now by reviewing all properties in your property portfolio, ensuring risk assessments are current, implementing proper control measures, documenting everything thoroughly, and building water safety into your regular routine using compliance tracking tools.

Practical steps to get started today

If you haven't yet addressed Legionella in your rental properties, start with these concrete steps.

Assess your current position across your portfolio. Identify which properties have had recent risk assessments and which need initial assessments. Note any properties with complex water systems that might benefit from professional assessment. Flag any properties with vulnerable tenants or those frequently vacant.

For each property requiring assessment, gather information about the water systems. Locate and document your hot water cylinder, cold water storage tanks if present, all taps and outlets, showers and other aerosol creating features, and age and condition of water systems.

Conduct or commission your risk assessments systematically. Start with highest risk properties, including:

• Those with elderly or vulnerable tenants

• Complex systems or multiple storage tanks

• Properties frequently left vacant, or

• Those with older, potentially problematic water systems.

Implement control measures identified through assessment. Address any immediate risks straight away. Schedule temperature adjustments and system improvements. Establish flushing regimes for vacant periods. Plan showerhead replacement and regular cleaning.

Document everything properly using the documents feature of your landlord software. Store completed risk assessments with other compliance documents. Set automatic reminders in August for reviews and checks. Record all maintenance and monitoring carried out.

Communicate with your tenants clearly. Update your tenant welcome pack with water safety information. Brief existing tenants on any new procedures. Make reporting easy through your maintenance system.

The bottom line on water safety

Legionella risk assessment might not grab headlines like Section 21 abolition or Making Tax Digital, but it's no less important to your legal compliance and duty of care.

Most domestic rental properties present low risk when basic control measures are in place. The assessment process needn't be complex or expensive for standard properties. What matters is understanding the risks, implementing appropriate controls, keeping good records, and reviewing periodically.

Think of Legionella management as part of responsible property management rather than a burdensome compliance task. The steps that control Legionella risk generally maintain water systems properly, prevent costly problems, and demonstrate professionalism to tenants.

Modern property management tools make tracking compliance straightforward, storing documentation securely, setting reminders automatically, and keeping you organised across your entire property portfolio.

Start with one property if you're feeling overwhelmed. Conduct the assessment, implement controls, document your work, and then replicate the process across your other properties. Once established, ongoing management takes minimal time whilst substantially reducing risk.

Your tenants deserve safe, healthy homes. Meeting your Legionella obligations is about legal compliance and its also more fundamentally about providing accommodation where people can live without fear of serious illness from simply turning on a tap or taking a shower.

Disclaimer: This article is a guide and not intended to be relied upon as legal or professional advice, or as a substitute for it. August does not accept any liability for any errors, omissions or misstatements contained in this article. Every effort was made to be accurate at the time of writing.