As a landlord in the UK, you have legal responsibilities to protect your tenants from legionella bacteria in the water systems of your rental properties. These duties apply whether you rent out a single house, multiple flats, or an HMO - and they apply to both residential and commercial lettings.
Understanding what you must do to comply with the law will protect your tenants' health, reduce your liability, and ensure you meet your obligations under COSHH regulations and the L8 Approved Code of Practice.
Have you completed a legionella risk assessment for your rental property?
Check your compliance status
Why landlords must manage legionella risks
Legionella bacteria can grow in water systems where conditions allow, particularly in water stored at temperatures between 20-45°C or where water stagnates. When water containing legionella is turned into a fine spray or mist (such as from showers), people can inhale the bacteria and develop Legionnaires' disease - a potentially fatal form of pneumonia.
As a landlord, you control the water systems in your rental properties, even though you may not live there. This makes you the "duty holder" under health and safety law, responsible for assessing and controlling legionella risks.
Your responsibility as a landlord exists regardless of property size or type. Whether you rent out a single bedroom, a family house, or a large HMO, you have duties under COSHH to protect tenants from legionella.
Legal framework for landlords
Health and Safety at Work Act 1974
Section 3 places a duty on anyone who has control of premises to protect "persons other than their employees" - including tenants. You must ensure, so far as is reasonably practicable, that tenants are not exposed to health and safety risks.
Control of Substances Hazardous to Health Regulations 2002 (COSHH)
Legionella bacteria are classified as a biological agent under COSHH. Regulation 6 requires you to:
- Assess the risk from exposure to legionella
- Prevent or control that risk
- Ensure control measures are used and maintained
- Keep records of the assessment and control measures
ACOP L8: Legionnaires' disease
The HSE's Approved Code of Practice L8 provides practical guidance on managing legionella risks. L8 explicitly confirms that landlords are duty holders, stating:
"Landlords have responsibilities for the water systems they control. This includes domestic landlords with rental properties."
While not law itself, ACOPs have special legal status. If you follow L8 guidance, you'll be considered to have met your legal duty. If you choose a different approach, you must demonstrate it achieves equivalent safety standards.
Landlord and Tenant Act 1985
Section 11 requires landlords to keep installations for water supply in proper working order. While this primarily addresses functionality, it reinforces that water system safety is a landlord responsibility.
Failure to conduct a legionella risk assessment is a breach of COSHH regulations. HSE can issue improvement notices, prohibition notices, and prosecute landlords. If a tenant contracts Legionnaires' disease and you haven't fulfilled your duties, you could face unlimited fines or even imprisonment.
What landlords must do
Your legionella responsibilities involve four key steps:
1. Conduct a legionella risk assessment
You must identify and assess sources of legionella risk in your rental property. This involves:
Identifying water systems:
- Hot water storage (cylinders, boilers, immersion heaters)
- Cold water storage tanks (if present)
- All taps, showers, and water outlets
- Any other water systems (garden taps, outside showers)
Assessing risks:
- Temperature ranges (is water stored at safe temperatures?)
- Stagnation risks (are any outlets rarely used?)
- Dead legs (unused pipe sections)
- System condition (age, maintenance, scale buildup)
Documenting findings:
- What risks have been identified
- Who might be at risk
- What control measures are needed
- When the assessment should be reviewed
Timeframe: Before a new tenancy begins, or as soon as possible if you already have tenants and haven't completed an assessment.
2. Implement control measures
Based on the risk assessment, you must implement practical controls to prevent legionella growth:
Temperature control (primary defence):
- Hot water stored at 60°C minimum
- Hot water delivered at taps/showers at 50°C minimum (within 1 minute)
- Cold water stored below 20°C
Prevent stagnation:
- Remove or flush little-used outlets weekly
- Ensure all outlets are used regularly
- Remove dead legs where possible
System maintenance:
- Service boilers annually
- Clean and disinfect storage tanks annually (if present)
- Descale showerheads quarterly
- Keep cold water tanks covered and insulated
Timeframe: Implement controls promptly after the risk assessment identifies them, prioritizing high-risk issues.
3. Keep records
You must maintain written records demonstrating compliance:
Risk assessment documentation:
- Copy of the completed risk assessment
- Date of assessment and assessor details
- Findings and recommendations
- Review schedule
Control measure records:
- What control measures are in place
- When they were implemented
- Who is responsible for maintaining them
Monitoring records (if applicable):
- Temperature checks
- Flushing schedules
- Maintenance activities
- Any water test results
Retention period: Keep records for at least 5 years, or for the duration of the tenancy plus 5 years.
4. Review regularly
The risk assessment must be reviewed:
- At least every 2 years
- When the property changes (renovations, new boiler, plumbing alterations)
- When tenancy changes (new tenants may use the property differently)
- If control measures fail (temperatures out of range, system defects)
Landlord Legionella Control Schedule
Complete legionella risk assessment before first tenant moves in
If assessment identifies rarely-used taps or showers, establish flushing routine
Clean and descale showerheads to prevent biofilm buildup
Annual boiler service ensures hot water temperature control
Clean and disinfect cold water storage tanks if present
Full review of assessment, or sooner if circumstances change
Different property types and their requirements
Single rental houses and flats
Typical risk level: Low to medium
Common systems:
- Combination boiler (no hot water storage) or hot water cylinder
- Direct cold water from mains (or small header tank in loft)
- Standard taps and showers
Key considerations:
- Combi boilers are lower risk (no hot water storage)
- Properties with cylinders need temperature checks
- Ensure all outlets are used regularly
- Check for dead legs from previous alterations
Assessment approach: Simple risk assessments using HSE landlord guidance or templates are typically sufficient for straightforward properties with standard domestic systems.
Houses in Multiple Occupation (HMOs)
Typical risk level: Medium to high
Common systems:
- Larger hot water cylinders or multiple boilers
- More complex distribution systems
- Multiple showers and bathrooms
- Potentially little-used outlets (vacant rooms)
Key considerations:
- Higher occupancy creates more exposure opportunities
- Greater variation in usage patterns
- More outlets increase stagnation risk
- Licensing requirements may include water safety checks
Assessment approach: Professional assessment recommended due to complexity and higher risk. More rigorous monitoring and record-keeping expected.
Student accommodation
Typical risk level: Medium to high
Specific issues:
- Long vacation periods (water stagnation)
- High turnover of tenants
- Inconsistent maintenance by occupants
- Multiple bathrooms and shower facilities
Key control measures:
- Flushing regime during vacation periods
- Pre-occupancy flushing before new tenants arrive
- Clear tenant guidance on shower use
- Regular monitoring during term time
Holiday lets and short-term rentals
Typical risk level: Medium to high
Specific issues:
- Periods of non-occupancy between guests
- Water systems may sit unused for days or weeks
- High guest turnover
- Less oversight than long-term lets
Key control measures:
- Flush all outlets before each new guest arrival
- Consider automatic flushing systems
- Weekly flushing if property is vacant
- Temperature checks before occupancy
Commercial lettings
Typical risk level: Medium to high
Considerations:
- Offices, shops, and commercial units have legionella risks
- Duty may be shared between landlord and tenant
- Ensure lease clearly defines who controls water systems
- Communicate responsibilities clearly
For commercial lettings, the party with control over the water system is typically the duty holder. Often this is the tenant, but if you as landlord maintain control (common in serviced offices), the duty remains yours. Always clarify this in the lease agreement.
Can you conduct your own risk assessment?
For simple residential rental properties with standard domestic water systems, you can conduct your own legionella risk assessment, provided you:
Have appropriate knowledge
- Understand legionella risks and how it grows
- Understand your water systems
- Can interpret L8 and HSG274 guidance
- Have undertaken basic training (recommended but not mandatory)
Have the right property type
Suitable for DIY assessment:
- Single house or flat with standard plumbing
- Combination boiler with no hot water storage
- Direct mains cold water supply (no tanks)
- Regular occupancy with all outlets used frequently
- No special features (spa pools, complex pipework)
Requires professional assessment:
- HMOs with multiple occupants
- Properties with hot water storage tanks (cylinders)
- Properties with cold water storage tanks
- Complex plumbing or multiple bathrooms
- Holiday lets or short-term rentals
- Commercial premises
- Any system with cooling towers or spa pools
Use quality resources
- HSE guidance for landlords
- COSHH L8 Approved Code of Practice
- HSG274 Part 2 (hot and cold water systems)
- Professional templates (ensure they're comprehensive)
DIY vs Professional Assessment for Landlords
DIY Assessment
- •Suitable for simple rental properties
- •Lower cost (but requires your time)
- •You maintain control and understanding
- •Must have adequate knowledge and training
- •You take full responsibility for accuracy
- •May lack technical detail or credibility
Professional Assessment
Recommended- •Required for complex properties and HMOs
- •Higher upfront cost but comprehensive
- •Expert knowledge and experience
- •Detailed technical recommendations
- •Liability protection and credibility with HSE
- •Ongoing support and monitoring often included
Bottom line: For a single, simple rental house with a combi boiler, DIY assessment may be acceptable if you're competent. For HMOs, properties with storage tanks, holiday lets, or anything complex, professional assessment is strongly recommended and often essential.
Implementing control measures
Once you've identified risks, you must implement the recommended controls. Here's what this typically involves:
Temperature management
Hot water systems:
- Set cylinder thermostat to 60°C minimum
- Check temperature at the cylinder with a thermometer
- Test outlet temperatures (should reach 50°C within 1 minute)
- If below target, service boiler or adjust thermostat
- Consider thermostatic mixing valves (TMVs) to prevent scalding while maintaining safe storage temperatures
Cold water systems:
- Insulate cold water tanks to prevent warming
- Keep tanks in cool locations (loft insulation away from tank)
- Check tank lids are secure and insulated
- Monitor cold tap temperatures (should be below 20°C)
Preventing stagnation
Little-used outlets:
- Identify taps, showers, or toilets rarely used
- Flush weekly for 2 minutes
- Consider removing redundant outlets
- Document flushing activities
Dead legs:
- Identify unused pipe sections (e.g., from removed sinks)
- Remove or cap as close to the main pipe as possible
- Dead legs should be less than 2 meters if unavoidable
During void periods:
- Flush all outlets weekly when property is vacant
- Run taps and showers for 2 minutes
- Consider asking tenants to do final flush before vacating
Maintenance activities
Annual tasks:
- Service boiler (hot water temperature control)
- Inspect and clean cold water tanks (if present)
- Disinfect water systems if recommended by risk assessment
- Check showerheads and descale/clean
- Review all control measures
Quarterly tasks:
- Descale showerheads and hoses
- Check TMVs are functioning correctly
- Visual inspection of accessible pipework
Between tenancies:
- Flush all outlets before new tenants move in
- Check water temperatures
- Inspect and clean showerheads
- Update risk assessment if property changes
If your property has been vacant for more than a week, run all taps and showers for at least 5 minutes before new tenants move in. For longer periods (months), consider professional flushing and disinfection.
Ongoing monitoring and maintenance
Your duties don't end once you've completed the initial risk assessment. Ongoing vigilance is essential:
Regular monitoring
What to monitor:
- Water temperatures at taps and showers
- Condition of showerheads and outlets
- Cold water storage tanks (if accessible)
- Boiler operation and hot water delivery
How often:
- Simple properties with low risk: Annual checks during routine maintenance
- Properties with storage tanks: Quarterly temperature checks
- HMOs and high-risk properties: Monthly temperature monitoring
- Holiday lets: Before each new occupancy
Who monitors:
- You can conduct monitoring yourself
- Appoint a competent agent (managing agent, maintenance contractor)
- Use a specialist water hygiene company for complex systems
Record keeping
Maintain records of:
- Initial risk assessment and all reviews
- Temperature monitoring logs
- Flushing schedules and activities
- Boiler service records
- Tank cleaning certificates
- Any water test results
- Correspondence with tenants about water safety
Storage: Keep records for at least 5 years in an accessible format (paper or electronic).
Tenant communication
At move-in:
- Provide tenants with information about water safety
- Explain importance of regular shower use
- Instruct on flushing protocols if away for extended periods
- Provide emergency contact information
During tenancy:
- Notify tenants before temperature monitoring visits
- Inform tenants of any maintenance affecting water supply
- Respond to tenant reports of water issues promptly
At move-out:
- Conduct exit inspection including water systems
- Flush all outlets if property will be vacant
- Update records
Tenants have a responsibility to cooperate with your legionella control measures. Your tenancy agreement should include provisions allowing access for water safety monitoring and maintenance.
Water testing: Do landlords need it?
A common misconception is that landlords must test water for legionella annually. This is not always the case.
When testing is required
Water sampling is only necessary if your risk assessment identifies it as needed. Testing may be appropriate when:
- Risk assessment indicates medium to high risk
- Control measures cannot adequately manage risks
- Verification of control effectiveness is needed
- After system remediation or disinfection
- Following a case of Legionnaires' disease
When testing is not required
For most simple domestic rental properties:
- Combination boilers with no storage
- Well-maintained systems with good temperature control
- Regular occupancy and water use
- No identified high-risk features
In these cases, proper temperature management, regular flushing, and maintenance are sufficient. Routine testing adds cost without improving control.
If you do test
Use accredited laboratories:
- UKAS accredited for legionella testing
- Sampling conducted by competent person
- Follow BS 7592 sampling methodology
Typical testing frequency:
- High-risk systems: Quarterly
- Medium-risk systems: Annually
- Low-risk systems: Every 2 years or as assessment dictates
Interpreting results:
- Under 100 CFU/L: Low risk, maintain controls
- 100-1000 CFU/L: Review controls, retest, investigate
-
1000 CFU/L: High risk, immediate action, consider disinfection
The HSE has clarified that for simple domestic properties, landlords do not automatically need to conduct water testing. Temperature control and regular use are the primary defences. Testing should be based on risk assessment findings, not a default requirement.
Sharing responsibilities with tenants
While you as landlord have the primary duty, tenants also have some responsibilities:
Landlord responsibilities (cannot be delegated)
- Conducting legionella risk assessment
- Implementing structural control measures (temperature settings, removing dead legs)
- Providing safe water systems
- Annual maintenance (boiler service, tank cleaning)
- Keeping records
- Reviewing risk assessment
Tenant cooperation required
- Allowing access for inspections and monitoring
- Reporting water system problems promptly
- Using showers and taps regularly
- Not tampering with temperature controls
- Flushing outlets after extended absences
Clear communication
Your tenancy agreement should:
- State landlord responsibilities for water safety
- Require tenant cooperation with monitoring
- Provide notice periods for access
- Outline tenant duties to report defects
- Include contact information for water safety issues
Landlord prosecution - failure to assess legionella risks
A landlord renting out three residential properties had never conducted legionella risk assessments. During an HSE inspection triggered by a tenant complaint about general property conditions, the lack of legionella control was discovered. While no one had become ill, the landlord was in clear breach of COSHH.
- ✗No legionella risk assessments for any rental properties
- ✗Landlord unaware of legal duties under L8
- ✗No temperature monitoring or control measures
- ✗Cold water storage tanks in poor condition and uncovered
- ✗Showerheads heavily scaled and never cleaned
- ✗No records of any water safety management
HSE served three improvement notices requiring immediate risk assessments for all properties and implementation of control measures within 30 days. The landlord was prosecuted for the breach, fined £12,000 plus costs, and given 6 months to demonstrate full compliance or face prohibition notices preventing further lettings.
Ignorance of the law is not a defence. All landlords, regardless of portfolio size, must comply with legionella regulations. HSE takes enforcement action even when no illness has occurred if duty holders fail to assess and control risks.
Managing legionella during property changes
Certain events require additional legionella management:
Property renovations or alterations
Before work begins:
- Update risk assessment to account for changes
- Brief contractors on water safety procedures
- Consider flushing regime during works
During renovation:
- Prevent contamination of water systems
- Protect tanks and equipment
- Manage dust and debris
After completion:
- Flush entire system thoroughly
- Disinfect if significant plumbing work done
- Update risk assessment and schematics
- Test temperatures before tenants return
Boiler replacement
- Flush system to remove sediment
- Set new boiler to 60°C minimum
- Verify outlet temperatures reach 50°C
- Update risk assessment documentation
- Provide tenant with new system information
Property acquisition
When purchasing a rental property:
- Request previous legionella risk assessment
- If none exists, conduct one before first letting
- Check condition of water systems
- Consider professional survey for older properties
- Budget for any remedial works identified
Change of managing agent
- Transfer all legionella records to new agent
- Ensure new agent understands requirements
- Clarify who is responsible for ongoing monitoring
- Review and confirm control measures remain in place
Common mistakes landlords make
"I had the gas safety check, so I'm covered"
Wrong. Gas safety certificates and legionella risk assessments are separate legal requirements. Gas engineers may not check legionella risks unless specifically instructed.
"My tenant deals with the water system"
Wrong. You cannot delegate your legal duty to assess and control legionella risks to tenants. While tenants should cooperate, the primary responsibility remains with the landlord.
"The property is new, so there's no risk"
Not necessarily. New properties can have legionella risks, particularly during commissioning when water may stagnate, or if systems are poorly designed with oversized tanks or dead legs.
"I'll do a risk assessment when a tenant asks for one"
Wrong. You must conduct the assessment before letting the property or as soon as possible if already let. Waiting for a tenant request means you're already in breach.
"An online template is sufficient"
Maybe, but be careful. Generic templates can help structure an assessment, but you must adapt them to your specific property. Simply ticking boxes without genuine evaluation won't meet legal requirements.
"I only need to test the water, not do a full assessment"
Wrong. Water testing alone doesn't fulfill your duty. You need a full risk assessment that identifies hazards, evaluates risks, and prescribes control measures. Testing may or may not be part of this.
The most dangerous mistake is assuming you don't have legionella duties because you "only" rent out one or two properties. Size of portfolio is irrelevant - if you control the water systems, you're the duty holder under COSHH.
Enforcement and penalties
HSE enforcement powers
If you fail to comply with legionella regulations, HSE can:
Issue improvement notices:
- Require you to take specific actions within a set timeframe
- Common for missing or inadequate risk assessments
- Failure to comply with notice is a criminal offence
Issue prohibition notices:
- Stop you from letting the property until compliance achieved
- Used when there is risk of serious personal injury
- Immediate effect, preventing new tenancies
Prosecute:
- Criminal prosecution for breaches of COSHH
- Tried in Magistrates' Court or Crown Court
- Penalties include unlimited fines and imprisonment
Penalties for non-compliance
Magistrates' Court:
- Maximum fine: £20,000 per offence
- Each property or breach can be a separate offence
Crown Court:
- Unlimited fines
- Up to 2 years imprisonment
- Typically reserved for serious breaches or where illness occurred
Typical fine levels:
- Failure to conduct risk assessment: £5,000-£15,000
- Inadequate control measures: £10,000-£30,000
- Negligence resulting in illness: £50,000+ and potential imprisonment
Civil liability
Beyond criminal prosecution, you could face:
- Civil claims from tenants who become ill
- Liability for negligence
- Compensation for injuries and losses
- Damage to reputation and difficulty re-letting
Insurance implications
Many landlord insurance policies require compliance with health and safety law. Non-compliance with legionella regulations could:
- Invalidate your insurance cover
- Lead to claim rejection
- Result in policy cancellation
Holiday let landlord fined after guest illness
A guest staying at a holiday cottage developed Legionnaires' disease after using the shower. Investigation found the property had been vacant for several weeks before the guest's arrival, allowing legionella to multiply in stagnant water. The landlord had no legionella risk assessment and no flushing procedures.
- ✗No legionella risk assessment for holiday let property
- ✗No flushing regime during vacant periods between guests
- ✗Water systems not flushed before guest arrival
- ✗Landlord unaware of heightened risks from intermittent occupancy
- ✗No records or control measures of any kind
- ✗Showerhead heavily contaminated with biofilm
The guest spent two weeks in hospital and made a full recovery. Public Health England traced the source to the holiday cottage through water sampling. HSE prosecuted the landlord, who was fined £25,000 plus £8,000 costs. The guest also pursued a civil claim for compensation, which was settled out of court for an undisclosed sum.
Holiday lets and short-term rentals carry higher legionella risks due to intermittent occupancy. Landlords must establish robust flushing procedures and conduct risk assessments that account for periods when properties are vacant. The financial and reputational consequences of neglecting these duties can be devastating.
Getting professional help
Many landlords benefit from professional assistance with legionella compliance:
When to use a specialist
Consider professional help if:
- You have multiple rental properties
- Properties have hot or cold water storage tanks
- HMOs or complex water systems
- Holiday lets or short-term rentals
- You lack confidence in conducting your own assessment
- You want liability protection and credibility
What to look for
Qualifications and memberships:
- Legionella Control Association (LCA) membership
- City & Guilds legionella qualifications
- Water Management Society membership
- Demonstrable experience with rental properties
Services offered:
- Comprehensive risk assessments
- Written scheme of control
- Template monitoring forms
- Ongoing support and advice
- Water sampling (if required)
- Training for landlords or agents
Costs:
- Simple rental property assessment: £150-£300
- HMO or complex property: £300-£800
- Ongoing monitoring packages: £100-£500 per year
- Water sampling: £50-£150 per sample plus lab costs
Choose a specialist with specific experience in rental properties. Assessments for commercial premises differ from residential lettings, and you need practical, proportionate advice suited to landlord duties.
Frequently asked questions
Yes. The legal duty under COSHH applies to all landlords who control water systems, regardless of how many properties you own. Even renting out a single house or flat requires you to assess legionella risks.
For a simple house or flat, professional assessments typically cost £150-£300. HMOs or properties with complex systems may cost £300-£800. You can conduct your own assessment for free if you're competent, though this requires time and knowledge.
No. Each property must have its own risk assessment because water systems, usage patterns, and conditions vary. However, if you have multiple similar properties, you can use a template approach, adapting it for each specific property.
Your tenancy agreement should include provisions for access for health and safety inspections. Give proper notice (usually 24 hours). If a tenant persistently refuses, you cannot fulfill your legal duties - document all attempts and seek legal advice, as you may need to pursue eviction or a court order.
Not necessarily. Water testing is only required if your risk assessment identifies it as necessary. For most simple domestic rentals with good temperature control and regular use, annual testing is not needed. Focus on temperature management and maintenance instead.
The landlord is responsible for implementing and funding control measures. This includes the initial risk assessment, any necessary system improvements, annual maintenance, and monitoring. Tenants cannot be charged for complying with your legal duties.
There is no such thing as a 'legionella certificate' equivalent to a gas safety certificate. What you need is a written legionella risk assessment document. Some assessors provide a summary cover sheet, but the full assessment is what demonstrates compliance.
Flush all outlets (taps, showers, toilets) thoroughly before new tenants move in, especially if the property has been vacant for more than a week. Run each outlet for at least 5 minutes. Check water temperatures, clean showerheads, and update the risk assessment if needed.
Yes, you should. Include provisions requiring tenant cooperation with monitoring, allowing access for inspections, and obliging tenants to report water system defects. However, you cannot delegate your duty to assess and control risks to the tenant.
While not legally required to provide them to the buyer, it's good practice. The new owner (if they continue letting) will need to conduct their own risk assessment or review yours. Providing existing records demonstrates responsible property management and may support the sale.
Summary: Your landlord legionella checklist
Before first letting or as soon as possible:
- Conduct a legionella risk assessment for each rental property
- Identify all water systems, outlets, and potential risks
- Implement recommended control measures (temperature settings, dead leg removal, etc.)
- Set up monitoring and flushing schedules
- Arrange annual boiler servicing
- Keep written records of assessment and controls
Ongoing responsibilities:
- Monitor water temperatures (frequency depends on risk level)
- Flush little-used outlets weekly if identified in assessment
- Service boiler annually
- Clean and descale showerheads quarterly
- Inspect and clean cold water tanks annually (if present)
- Keep records of all monitoring and maintenance
At tenancy changes:
- Flush all outlets before new tenants move in
- Check water temperatures
- Update risk assessment if property has changed
- Provide new tenants with water safety information
Every 2 years or when circumstances change:
- Review and update risk assessment
- Implement any new recommendations
- Update records
Need help understanding your landlord legionella duties or conducting risk assessments? A qualified water hygiene specialist can assess your rental properties, implement control measures, and provide ongoing support to ensure full compliance.
Related articles
- What is a Legionella Risk Assessment?
- What is Legionella?
- Legionella Testing Guide
- Do I Need a Legionella Assessment?
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Disclaimer: This guidance is for general information and is based on UK law and HSE guidance. It does not constitute legal or professional advice. For specific situations, consult a qualified water hygiene specialist or health and safety advisor. Laws and guidance may change.