Building Handover Water Hygiene: A Practical Guide
Building handover is the point where Legionella responsibility moves from the project team to the people who will run the building, and it is the point where gaps most often open up. A sound handover means the water system has been flushed, disinfected and tested before use, the records are complete, and a named person knows what to do on day one. This guide sets out what to agree, check and hand over, so the incoming facilities, estates or compliance team starts with a system that is under control.
It is written for facilities managers, estate managers, health and safety managers and compliance managers taking over new-build, refurbished or newly acquired sites, whether commercial, education, healthcare or housing.
TL;DR
Any new water system needs, as a minimum, flushing and disinfection before it is brought into use. Do not treat that as optional paperwork.
The gap between filling the system and normal use is the riskiest period microbiologically, so plan occupation dates and interim flushing before handover, not after.
Insist on a complete handover pack: commissioning records, O&M manuals, a risk assessment and evidence of sampling results.
Agree who owns water hygiene on the day of handover, and make sure that person is trained and has the system information.
Keep the contractors reachable after handover so defects can be put right, and review the risk assessment once the building is operating.
Table of Contents
Why handover is the riskiest moment for water hygiene
A new or refurbished system looks clean, but it has often been pressure tested with water, left standing, and then left again while finishing trades complete. HSE technical guidance says the period between filling and bringing a system into normal use is potentially the most hazardous microbiologically. Warm, stagnant water in unused pipework, tanks and outlets is where Legionella and other organisms can establish themselves.
Handover adds a second problem: a change of hands. The project team knows how the system was built, filled and tested. The facilities team knows how the building will be used. Unless the information is passed across deliberately, neither has the full picture, and the building can open with no written scheme, no named responsible person and no baseline sample results.
The legal frame does not change because the building is new. HSE’s approved code of practice, L8, says that where there is a reasonably foreseeable risk of exposure, a written scheme should be prepared for preventing or controlling the risk. Whoever is in control of the premises at occupation inherits that duty.
Agree responsibilities before the keys change hands
The best handovers settle water hygiene months before practical completion. Four questions need a written answer.
Who is the duty holder from the day of occupation?
Name the organisation in control of the premises and the individual who will manage Legionella control day to day. If the building is leased, the lease or management agreement should say which party carries which task: risk assessment, sampling, temperature checks, remedial work and record keeping.
Who is involved at design and construction stage?
Healthcare guidance is the clearest on this and is a good model for any sector. Health Technical Memorandum 04-01 says that where new premises are planned or existing ones refurbished, the Water Safety Group should be consulted at the earliest possible opportunity, so total water hygiene requirements can be assessed in the planning stages. One NHS trust’s policy goes further, requiring its Head of Capital Projects to alert the Water Safety Group at the earliest opportunity when premises are to be built, altered or refurbished.
You may not have a Water Safety Group, but the principle applies: the person who will own water hygiene should be in the project conversation before the pipework is closed up.
Are contractors competent?
The same trust requires external consultants and contractors to be suitably qualified, trained and competent before a project starts, with evidence such as qualifications and membership of schemes including WaterSafe and the Legionella Control Association held on file. Ask for the same evidence from anyone who commissions, disinfects, samples or assesses your system.
What happens if something is wrong after handover?
That trust also requires designers, consultants and contractors to be retained after handover through “soft landings”, so defects or performance problems can be investigated and resolved. Build a similar clause into your contract: a defined period in which the project team returns to fix water system defects at their own cost.
What should be completed before occupation
Commissioning
HSG274 Part 2 defines commissioning as bringing a new system into operation. Its aims include checking the system performs to its design specification, identifying leaks and balancing hot water flow. Ask for the commissioning certificates and flow and temperature readings, outlet by outlet where possible.
Flushing and disinfection
The same guidance states that any new water system will require, as a minimum, flushing and disinfection before being brought into use. Your handover pack should include:
the date, method and disinfectant used for each system (cold water storage, hot water, any calorifiers and tanks)
the contact time and concentrations achieved
who carried it out and their competence evidence
confirmation that the system was flushed through to every outlet afterwards
We carry out water tank cleaning and system disinfection for sites across the UK, including cold water tank repair or replacement where the survey shows it is needed.
Water sampling before use
Sample results give you a baseline. NHS Scotland’s infection control manual says that for commissioning, the Water Safety Group should approve a full set of analysed water sample results before handover and before the system goes into clinical use, confirming that the water is of potable quality. That is Scottish healthcare guidance, but the sequence is sensible anywhere: results first, occupation second.
Depending on the building, a baseline set might include Legionella, total viable count, Pseudomonas aeruginosa (important in healthcare and wherever vulnerable people are present), potable water quality and, for heating and chilled circuits, closed system water tests. Our Legionella water testing and analysis starts from £55 per sample, and we also cover the wider microbiological, chemical, pH and conductivity tests listed on that page. For healthcare settings, our guide to types of water hygiene testing in healthcare explains which tests apply where.
Thermostatic mixing valves and outlets
Where the building has TMVs, they should be commissioned, labelled and entered on the asset register, with a servicing schedule from day one. We provide TMV servicing and general remedial works so a failed valve found at handover is dealt with before occupation.
The gap between filling and occupation
Opening dates slip. Water systems do not wait. HSG274 Part 2 says that where there is a prolonged period between pressure testing with water and full occupation, weekly flushing should be implemented to reduce stagnation and the potential for microbial growth, keep temperatures below 20°C, and keep residual chemical treatment levels, for example a low level of chlorine in the incoming supply, maintained throughout the system.
In practice:
Ask the contractor for the date the system was first filled.
Ask for the flushing log from that date to handover. Gaps in it matter.
If occupation is delayed after handover, assign weekly flushing to a named person and record it.
If the log has gaps or temperatures have drifted, repeat disinfection and sampling before people use the building.
Automated temperature monitoring can help on large or partly occupied sites, because it records cold and hot water temperatures continuously and flags drift between visits. Details are on our automated water temperature monitoring page.
The handover pack: what to ask for
One NHS trust requires that commissioning and handover records, O&M manuals and risk assessments, with evidenced records, are received on completion of a project. Use that as the minimum standard for any sector. The table below turns it into a checklist.
Document | What it should show | Why you need it |
As-built schematics | Current layout of cold, hot and return pipework, tanks, calorifiers, TMVs | The written scheme needs an up-to-date plan, and so does the risk assessment |
Commissioning records | Design flows, temperatures, leak checks, balancing | Proves the system performs as designed |
Flushing and disinfection certificates | Dates, method, concentrations, contact times, competent person | Evidence the minimum pre-use control was done |
Sample results | Laboratory reports for every agreed sample point | Your baseline for future trend comparison |
Flushing log | Weekly flushing from first fill to handover | Shows stagnation was controlled |
O&M manuals | Maintenance tasks and intervals for each asset | Feeds the planned preventive maintenance schedule |
Asset register | Tanks, TMVs, outlets, filters, dosing units | Defines what the logbook must cover |
Contractor competence evidence | Qualifications, scheme memberships | Shows the work was done by competent people |
Risk assessment | Legionella risk assessment of the completed system | Required before the building is used |
Do not sign off a handover with missing items. Record what is missing, who owes it and by when, and make it a condition of final payment or retention release where your contract allows. Pursuing an outstanding certificate a year later is far harder than agreeing the list on handover day.
Risk assessment and written scheme
A risk assessment should exist before the building is used and should be revisited when it is running. Health Technical Memorandum 04-01 says water risk assessments should be completed for all projects, with the risk assessment reviewed once the system is operational. One trust requires assessments at each project stage, at least before commencement and once the system is operational.
From the risk assessment comes the written scheme. L8 says it should include an up-to-date plan or schematic, a description of safe operation, precautions, checks and their frequencies, and remedial action if the scheme is not effective. Where treatment regimes are used, it should also cover control parameters and tolerances, sampling locations, test frequencies and procedures, remedial measures and emergency procedures.
Our Legionella risk assessments start from £185 and are written for the specific site, which is how a handover assessment should work: the assessor walks the as-built system against the schematics in the pack. If you already have an assessment from the construction phase, our guide to reviewing a Legionella risk assessment shows what to look for when the building starts operating.
Training the incoming team
The handover pack is only useful if the people receiving it can use it. The incoming responsible person and deputies need to understand:
how the water systems are laid out and where the high-risk assets sit (storage tanks, calorifiers, little-used outlets, TMVs)
what the written scheme requires, at what frequency and who does each task
how to record results in the logbook and what readings trigger action
who to call, and what to do, if a result is out of range
Build a formal walk-through of the plant rooms and key outlets into the handover programme, led by the commissioning contractor, with the facilities team present and the schematics in hand. Treat training as a deliverable with a date and an attendance record, not a favour.
Our Legionella awareness training is available on-site or online, so a facilities team spread across several locations can be trained without travel.
A handover timeline that works
Stage | Water hygiene action |
Design and planning | Involve the future responsible person; agree competence requirements for contractors |
Installation and pressure testing | Record first-fill date; keep flushing log; limit stagnation |
Pre-handover | Flush, disinfect, sample; agree handover document list |
Handover | Check pack against list; walk the plant; log defects and missing items |
Occupation | Responsible person in place; written scheme and logbook running; weekly flushing if occupation is delayed |
First months | Review risk assessment once operating; compare results with baseline; contractors available for defects |
Handover when you acquire an existing building
Not every handover follows construction. If you take on an existing building through purchase, a lease or a change of managing agent, the same logic applies, with the history of the system as the unknown. Ask the outgoing party for the last risk assessment, the logbook, recent sample results, the asset register and details of any remedial work still open. If these are out of date or missing, commission a fresh assessment early, because the system’s condition is the first thing a new duty holder is responsible for understanding.
A change of use, such as an office becoming a clinic or a school adding a swimming facility, has the same effect: the assessment should be reviewed because people and water use are different. Our case study on Legionella control in business premises shows how this works on a commercial site.
Most of the Legionella problems we are asked to fix after a building opens trace back to the same few things: nobody named as responsible, no baseline results, and a handover pack that was filed rather than read. None of these is expensive to prevent. Our approach is to treat handover as the first compliance review of the building, not the last job of the project. We prefer to be involved before practical completion, so the risk assessment, sampling plan, logbook and training are ready when the keys are handed over. Because each site is different, we write the control programme around your building and your team, not from a template. If you take only one thing from this guide: do not accept the building until the water hygiene file is complete and someone owns it. Sammi
Our view on handover
How we can support your handover
We work with commercial, education, healthcare, housing and public sector clients across the UK on exactly this stage: Legionella risk assessments, water sampling, disinfection, TMV servicing, training, logbook implementation and ongoing consultancy. Whether you are the project team preparing a pack or the facilities team inheriting one, we can review what you have and close the gaps.
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Start with a Legionella risk assessment from £185, or contact us through our site to talk through a quote for the full handover package.
FAQ
Do new buildings need a Legionella risk assessment?
Yes. HSE’s L8 guidance expects a written scheme wherever there is a reasonably foreseeable risk, and the people in control of the premises must be able to show the risk has been assessed. A new system still has stagnation and temperature risks, particularly between first fill and occupation, so the assessment should exist before the building is used.
Is flushing and disinfection really required for new pipework?
HSG274 Part 2 says any new water system needs, as a minimum, flushing and disinfection before it is brought into use. Ask for the certificate and the method used, and keep it in the handover pack.
What if the building will not be occupied for weeks after handover?
Then stagnation is the main concern. HSG274 Part 2 advises weekly flushing where there is a prolonged gap between pressure testing and full occupation, with temperatures kept below 20°C and chemical residuals maintained. Name the person responsible for flushing and keep a log.
Who is responsible for water hygiene once the building is handed over?
The organisation in control of the premises is the duty holder, and it should appoint a competent person to manage day-to-day control. Agree this in writing before handover so there is no period when nobody owns the system.
Can the contractor be asked to return if tests fail after handover?
Only if the contract says so. Build in a post-handover defects period, similar to the soft landings approach NHS trusts use, so designers and contractors are obliged to investigate and fix problems.
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