Legionella Risk Assessment for Landlords: A 2026 Guide

You're probably doing the usual pre-tenancy checks right now. Gas booked. EICR filed. Smoke alarms tested. Then someone mentions legionella and the whole thing goes fuzzy, because there's no obvious certificate to chase and half the advice online turns into legal jargon within two paragraphs.

That's where most landlords get stuck.

Legionella compliance isn't about buying another document for the file. It's about proving you've looked at the water system, understood where risk sits, and put sensible controls in place. For a modern flat, that may be straightforward. For an older house or a block with more complicated pipework, it takes a more careful approach. Either way, the costly mistake is assuming that because there's no standard certificate, there's no real duty.

Why Legionella Risk Is a Landlord's Responsibility

A rental property doesn't stop being a health issue once the gas and electrics are sorted. Water systems can create their own problems, especially where water sits still, temperatures drift into the wrong range, or parts of the system aren't being used properly.

That matters because legionella risk sits squarely within a landlord's duty of care. In practice, we're responsible for making sure the property is safe to occupy, and that includes the way hot and cold water is stored, distributed, and used. It's less visible than a broken handrail or a failed boiler, but the responsibility is no less real.

Why this catches landlords out

The confusion usually starts with one question. “Do I need a certificate?”

For domestic rentals, the issue isn't a certificate-led regime in the same way as gas safety. The primary task is managing the risk properly. That means looking at the property's water system with a practical eye, not treating it as a paperwork exercise.

A simple modern flat with regular use may present a low and manageable risk. An older London house with leftover pipe runs, a cold water tank, and periods of vacancy is a different proposition. The landlord's obligation applies to both. The difference is in how much control work is needed.

Good compliance is usually quiet. You won't notice it because the system is clean, temperatures are right, and the records are there if anyone asks.

Healthy homes start with water systems

Landlords often think about plumbing only when there's a leak, a pressure issue, or a tenant complaint. That's too late. Water hygiene is part of the property's overall condition, which is why broader resources on healthy housing can be useful. EZ Plumbing's guide to healthy homes gives a sensible reminder that plumbing decisions affect day-to-day health, not just maintenance budgets.

For landlords, the practical takeaway is simple:

• Treat water safety as routine management: Include it in your pre-let and mid-tenancy checks.

• Match effort to the system: A combi boiler flat isn't the same as a property with tanks and older pipework.

• Keep evidence: If you assessed the risk and took action, you need a record of it.

Once you approach legionella that way, the job becomes clearer. It stops being a vague compliance worry and becomes another part of running a safe, well-managed property.

Decoding Your Legal Duties for Legionella Control

A lot of landlords get tripped up here because legionella law does not come with the tidy paperwork people expect. There is no domestic certificate to book, file, and forget. The duty still exists, and it sits with us as the person controlling the rental property and its water system.

Under the Health and Safety at Work etc Act 1974 and the Control of Substances Hazardous to Health Regulations 2002, landlords must assess and control the risk of exposure to legionella bacteria, following HSE guidance in ACOP L8, as explained in this summary of landlord obligations.

The point most landlords miss

The phrase that causes the confusion is “no certificate required.” Many landlords hear that and assume the whole issue is optional. It is not. What the law expects is a suitable risk assessment, carried out by someone competent, followed by sensible control measures that match the system you have.

For a straightforward flat with a combi boiler and regular occupancy, that may be a simple, documented assessment and routine checks. For a London conversion with old pipework, a stored hot water cylinder, or long vacant periods, the standard is the same but the work is heavier. The trade-off is practical, not legal. Lower-risk systems are easier to manage. Higher-risk systems need closer attention.

A missing certificate will not cause the problem. A missing assessment, poor control, or no records will.

What compliance looks like in plain English

Good legionella compliance is usually ordinary property management done properly. It means understanding where risk can develop and being able to show what you did about it.

For most landlords, that comes down to five jobs:

• Assess the system you have: Check for stored water, dead legs, little-used outlets, showers, tanks, and any parts of the plumbing that let water sit.

• Keep water out of the risk range where possible: Hot water is generally stored at 60°C, cold water is kept below 20°C, and systems should avoid conditions where water sits between 20°C and 45°C.

• Deal with stagnation: Redundant pipework, spare bathrooms, empty units, and long voids need attention.

• Review after changes: Plumbing alterations, a long vacancy, or a change in how the property is used should trigger a fresh look.

• Keep a record: Notes, dates, temperatures, flushing logs, and remedial work matter far more than a landlord's memory six months later.

This sits alongside your wider management duties, not outside them. If you already work through repairs, gas, electrics, smoke alarms, and tenancy issues in a structured way, legionella control belongs in the same system. This guide to landlords' legal responsibilities helps place it in that broader compliance picture.

The certificate myth

The lack of a formal certificate causes more wasted time than the assessment itself. Landlords search for a pass or fail document because that is how gas and electrics work. Legionella does not work like that in a standard domestic let.

What you need is evidence that someone competent looked at the water system, judged the risk, and set out any control measures. Sometimes that is a short written assessment for a simple flat. Sometimes it is a fuller report for a block, an older house split into lets, or a property with tanks and seldom-used outlets. The paperwork is only useful if it reflects the actual plumbing and the actions are carried out.

That point matters in urban portfolios. In London, we often deal with compact flats in busy occupation and older buildings altered over decades. Two addresses on the same street can need completely different control measures because the pipework history is different.

What tends to go wrong

The common mistakes are familiar.

One is using a generic online template and marking every property “low risk” without checking the actual system. Another is paying for an assessment, filing it away, and ignoring the actions. A third is focusing on water sampling as if that replaces day-to-day control. In normal domestic settings, the practical control point is usually the condition of the system, temperature control, and preventing stagnation.

Landlords do better when they keep the job simple. Know the layout. Check the parts that can create risk. Write down what you found and what you changed. That is the difference between paper compliance and genuine compliance.

A Step-by-Step Guide to Your Property Risk Assessment

A proper legionella risk assessment for landlords isn't complicated when you break it down by parts of the property. The recognised methodology includes five core stages: identify hazards, identify who is at risk, evaluate the risk level, implement control measures, then record findings and review periodically, as set out in this landlord assessment guide.

Start with the layout, not the form. Walk the property and follow the water route from source to outlet. That gives you a far better read than filling in a template first.

Look at the system as it really exists

Before you inspect anything, gather the basic facts. Is it a combi boiler flat, a house with a cylinder, or an older property with tanks? Are there ensuite bathrooms, outside taps, or little-used cloakroom basins? Has any plumbing been altered over the years?

Then inspect the places where risk tends to hide:

• Hot water plant: Check the boiler, cylinder, or calorifier arrangement. You're looking for whether the system can hold hot water at the right storage temperature and whether outlets are delivering properly.

• Cold water storage: If there's a tank, see whether it's secure, clean, and protected from warming up.

• Pipework: Watch for dead legs, long unused branches, and pipe runs that suggest old alterations.

• Outlets: Showers matter because they create aerosol. Low-use taps matter because water can sit in them for long periods.

Identify who is at risk

A lot of landlords skip this because they focus only on the building. The methodology doesn't stop there. You also need to think about the people using the property.

A standard tenancy with healthy adults presents one level of exposure. A property occupied by older tenants, people with compromised immunity, or anyone more vulnerable to respiratory illness needs more care in the assessment. Even if the plumbing looks ordinary, the consequences of poor control can be different.

Practical rule: Don't assess the pipework in isolation. Assess the pipework, the pattern of use, and the likely occupant together.

Evaluate what actually raises the risk

Not every issue carries the same weight. A shower in daily use is different from a shower in a vacant flat. A brand new, direct-fed system is different from an older arrangement with unknown modifications. Risk usually increases when three things combine: temperatures in the wrong range, stagnant water, and aerosol-producing outlets.

This is a useful point to pause and compare your observations:

Area	What to check	Why it matters
Hot water system	Can it store and deliver heat properly?	Poor temperature control supports bacterial growth
Cold system	Is water staying cool and moving?	Warm, stagnant cold water can become a problem
Pipework	Are there dead legs or redundant runs?	Unused sections create stagnant water
Outlets	Are some rarely used, especially showers?	Infrequent use raises stagnation risk

A visual demonstration can help if you're training staff or reviewing your own process:

https://www.youtube.com/watch?v=NC0jcTFIGKs

Turn observations into actions

Once you've inspected the property, don't leave the findings as vague notes. Write down the hazard, the reason it matters, and the action required. “Dead leg behind old sink branch, remove when plumbing works are next scheduled” is useful. “Water system appears fine” isn't.

For single lets, that process can be quick if the system is simple. For whole blocks, repeat the same thinking at two levels. First at plant and distribution level, then at flat and outlet level. Shared systems, risers, storage, and low-occupancy units all need attention.

The best assessments read as if a competent person physically walked the building. Because that's exactly what should have happened.

Implementing Effective Control Measures and Records

A risk assessment only protects you if it changes what happens on site. The practical controls are well established, and they're not complicated. The problem is that landlords often do them inconsistently or fail to record them.

One common pitfall is assuming that because no certificate is needed, no assessment or control record is needed either. That's exactly the misunderstanding warned about in this landlord compliance note on legionella control, which also states that 78% of UK landlord legionella incidents arise from stagnant water in unused properties during void periods and that 95% of domestic systems achieve safe control when hot water is stored at 60°C and outlets are verified above 50°C, with cold water consistently below 20°C.

The controls that work

Most domestic properties can be managed with straightforward preventative measures:

• Set hot water properly: Store hot water at 60°C and confirm it reaches outlets at above 50°C where appropriate.

• Keep cold water cold: Cold outlets and storage should stay below 20°C.

• Remove dead legs: Unused pipe sections are a recurring problem in altered properties, especially where kitchens or bathrooms have been moved.

• Flush little-used outlets: If a guest bathroom, ensuite, or utility sink barely gets used, it needs routine flushing.

• Maintain outlets: Shower heads and hoses need cleaning and descaling because scale and debris make control harder.

If you want a broader lay explanation of building-level prevention, this article on how to manage Legionella in your building gives a useful practical overview.

Records are your evidence

When landlords get challenged, the issue often isn't only whether the right thing was done. It's whether they can prove it was done. That's where a simple record sheet matters.

You don't need a glossy compliance folder. You need a clear log that shows the property, the checks, the readings, the action taken, and who did it.

Control Measure	Required Action	Frequency	Record to Keep
Hot water control	Confirm storage temperature and outlet performance	Periodically and after relevant changes	Date, location tested, temperature, initials
Cold water control	Check cold outlets or storage remain below target range	Periodically	Date, outlet or tank, temperature, action taken
Unused outlets	Flush infrequently used taps and showers	As part of routine management and void procedures	Date, outlet flushed, duration, initials
Dead leg management	Identify and remove redundant pipework	When found during inspection or works	Description of pipework, contractor or person responsible, completion date
Shower maintenance	Clean and descale heads and hoses	Periodically	Date cleaned, outlet, any replacement noted
Review notes	Update the assessment after changes	When tenancies, occupancy, or plumbing changes	Revised assessment date and summary of changes

A wider repair system helps keep this under control. If you already track reactive and planned works properly, legionella actions can sit inside the same maintenance discipline. That's the same operational thinking behind clear landlord repair responsibilities.

If it isn't written down, you're relying on memory. Memory is a weak defence.

Scheduling Reviews and Managing High-Risk Void Periods

Most landlords ask the wrong question about review timing. They ask, “Is this annual?” The better question is, “What would make my last assessment unreliable today?”

The HSE position is periodic review, especially when circumstances change. Best practice guidance often suggests reviewing at least every 2 years, and landlords should also revisit the assessment before a new tenancy begins or after an extended vacancy, according to this review guidance for landlords.

Periodic review versus event-driven review

Navigating legionella risk assessment can be complex for landlords. A fixed cycle is useful for diary management, but water systems don't always wait for the calendar. A property that was low risk last year may not be low risk after a void, a plumbing alteration, or a change in occupancy pattern.

Use both triggers:

• Periodic review: Keep a regular review date in your compliance diary.

• New tenancy review: Recheck the system before move-in, especially if the property has sat empty.

• Post-works review: Any material plumbing change deserves another look.

• Extended vacancy review: Empty properties need active control, not passive waiting.

If you run several properties, a central tracker helps. Teams that manage blocks or multiple lets usually need some kind of scheduled compliance dashboard, even if it's simple. Compliance monitoring tools for landlords are useful for that sort of portfolio-level organisation.

Void periods are where trouble starts

Void periods are the point where many otherwise decent systems become risky. Water stops moving. Temperatures drift. Little-used outlets become no-use outlets.

The practical protocol is clear. During voids, all water outlets should be flushed weekly for at least two minutes. That means taps, showers, and toilets. Before a new tenant moves in, the whole system should be thoroughly flushed again.

A short checklist keeps this manageable:

• Run every outlet weekly: Include basins, kitchen taps, baths, showers, outside taps, and toilets.

• Record the visit: Date, outlet, duration, and the person who carried it out.

• Check hot water performance before occupation: Make sure the system is operating properly before handover.

• Don't ignore hidden outlets: Cleaner's cupboards, utility rooms, and spare bathrooms are easy to miss.

Vacant properties don't stay low risk on their own. Someone has to keep the water moving.

Single lets and blocks need different routines

For a single flat, the void routine is usually simple enough for one person with a checklist. For a whole block, the challenge is consistency. Communal plant, risers, unoccupied units, and varying occupancy levels create more moving parts.

In urban portfolios, especially older London stock, I've seen the same pattern repeatedly. The risk doesn't come from one dramatic fault. It comes from small gaps in routine. A cupboard tap no one remembers. A vacant unit missed for two weeks. An outlet that wasn't included in the flushing log.

That's why review schedules should be practical, property-specific, and tied to actual use.

Deciding Between a DIY Assessment and a Professional

The law allows a landlord to carry out the assessment themselves if they're a competent person. In plain English, that means you understand the water system, the risk points, and the controls well enough to make a sound judgement. It doesn't automatically mean you need a third party for every property.

At the same time, not every landlord should do their own assessment. The right choice depends on the building, the occupants, and your confidence in reading what's in front of you.

When DIY usually makes sense

A self-assessment is often reasonable where the property is straightforward and the system is easy to understand.

That usually means things like:

• Modern flats with simple systems: Especially where a combi boiler serves a small number of outlets.

• Clearly laid out plumbing: No tanks, no mystery pipe runs, no sign of previous ad hoc alterations.

• Regular occupancy: Water moves through the system consistently.

• Landlords who know the basics: You can identify outlets, understand temperature control, and spot obvious stagnation risks.

In those cases, the assessment is often less about specialist analysis and more about disciplined inspection and record keeping.

When a professional is the safer call

There are situations where bringing in a specialist is the best decision.

Choose that route if you're dealing with:

• Older buildings with unknown pipework

• Blocks or houses with shared or more complex systems

• Properties with tanks, calorifiers, or extensive distribution runs

• Homes occupied by more vulnerable residents

• Repeated voids or low-use patterns across multiple units

• A system you don't fully understand

The NRLA notes that landlords often face confusion over review frequency, with a best practice recommendation of every two years sitting alongside a different legal minimum, and that this is especially relevant when managing void periods in social housing, as discussed in its landlord guidance on legionella.

The trade-off in real terms

DIY can save money and speed things up. Professional input can reduce uncertainty. Neither option is automatically right.

The core question is whether you can defend the assessment as sensible and competent. If you're hesitating because the system is complicated, that hesitation is useful information. It usually means you need another pair of eyes.

For many landlords, a mixed approach works best. Handle straightforward low-risk properties yourself. Use a professional for the awkward stock, the older houses, and the buildings where one hidden issue could affect multiple occupancies.

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If you want a hands-off landlord setup that keeps compliance, maintenance, and occupancy under one roof, SM Elite Management Ltd can help. They work with landlords and block owners across London, offering guaranteed rent arrangements, day-to-day management, and a compliance-focused approach that reduces void stress and protects the condition of the asset.