M&M Compliance Training
Legionella bacteria thrive in poorly managed water systems. In a domestic or commercial setting, an outbreak is serious. In a healthcare environment — where patients are elderly, immunocompromised, post-surgical, or critically ill — it can be fatal.
That is precisely why NHS water safety compliance is one of the most tightly governed areas of healthcare estates management. HTM 04-01: Safe Water in Healthcare Premises sets out comprehensive requirements for how NHS trusts must manage their water systems to control the risk from Legionella, Pseudomonas aeruginosa, and other waterborne pathogens.
This guide explains what HTM 04-01 requires, who is responsible, and what practical steps NHS Estates Managers and Water Safety Groups should take to ensure they remain compliant in 2026.
HTM 04-01 is the Department of Health and Social Care’s definitive guidance on safe water management in all types of healthcare premises — from acute hospital trusts to GP practices and community health centres. It covers the design, installation, operation, and maintenance of hot and cold water supply, storage, and distribution systems.
Crucially, it also sets out the management framework required to keep those systems safe: the governance structure, the roles and responsibilities, the monitoring requirements, the risk assessment process, and the training obligations that sit around all of it.
HTM 04-01 does not exist in isolation. It sits alongside HSE’s Approved Code of Practice L8 (the “Legionella ACOP”) and HSG274, and all three must be read together by anyone managing water safety in a healthcare setting. Where NHS-specific requirements go further than L8, HTM 04-01 takes precedence.
In Scotland, the equivalent guidance is SHTM 04-01, published by the Scottish Government Health Directorates. The principles are closely aligned with the English HTM 04-01, but Scottish NHS Boards should refer to the SHTM version for their specific compliance obligations. M&M Compliance Training provides water safety training and AP appointments aligned to both frameworks.
HTM 04-01 defines a layered governance structure. Understanding where each role sits is essential for NHS Estates Managers — and for any organisation commissioning water safety services.
The Responsible Person (Water)
Every healthcare organisation must nominate a Responsible Person (Water) — sometimes called the Nominated Person. This is a senior individual, typically within the trust’s management structure, who holds overall accountability for ensuring that the organisation meets its water safety obligations. The RP does not need to be a water engineer, but they must understand their responsibilities and must have access to the competent technical support needed to discharge them.
The Water Safety Group
HTM 04-01 requires healthcare organisations to establish a Water Safety Group (WSG). This multidisciplinary group brings together key stakeholders — including the Infection Prevention and Control team, the Estates team, the Authorised Person (Water), and the Authorising Engineer (Water) — to oversee the organisation’s water safety management programme. The WSG should meet regularly (at least quarterly is recommended) and must produce a Water Safety Plan.
The Authorised Person (Water)
The AP (Water) is the operationally competent individual responsible for the day-to-day management of water safety systems. They must have demonstrated knowledge of water hygiene, HTM 04-01, and the specific systems in the premises. The AP (Water) manages monitoring programmes, responds to adverse results, and interfaces with contractors carrying out water hygiene work.
The Authorising Engineer (Water)
The AE (Water) is the independent specialist who provides assurance that the trust’s water safety management meets the required standard. The AE audits the WSG’s work, reviews the Water Safety Plan, assesses and recommends AP (Water) appointments, and provides written annual assurance reports to the Responsible Person. Like all AE roles under HTM 00, the AE (Water) must be independent of the organisation.
A Water Safety Plan is not a document you produce once and file away. It is a live management tool — and the quality of that plan, and the rigour with which it is followed, is what sits between your patients and a Legionella outbreak.
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HTM 04-01 requires every healthcare organisation to produce and maintain a Water Safety Plan (WSP). This is the central document that records the organisation’s approach to water safety management and demonstrates compliance. A properly constructed WSP should include a site-specific Legionella risk assessment, a schematic of the water distribution system, a monitoring and inspection schedule, control measures for identified risk areas, responsibilities for each element of the programme, and records of all actions, results, and incidents.
Risk assessments should be reviewed at least every two years, or immediately following any significant change to the water system, a failure of control measures, or an incident. High-risk or complex systems warrant annual review.
Monitoring is the engine of water safety management. HTM 04-01 sets out specific monitoring requirements that go beyond the minimum required by L8. Key requirements include temperature monitoring of hot and cold water systems at representative outlets, microbiological sampling at defined frequencies, regular inspection of water storage tanks and cooling towers, TMV (thermostatic mixing valve) maintenance programmes, and management of deadlegs, infrequently used outlets, and other high-risk areas.
Augmented care units (ICUs, oncology wards, neonatal units) present the highest risk from Pseudomonas aeruginosa as well as Legionella. HTM 04-01 Part B provides specific guidance on point-of-use filtration, outlet management, and enhanced monitoring requirements for these areas. NHS trusts should ensure their Water Safety Plan explicitly addresses augmented care provision.
HTM 04-01 does not treat water safety training as optional. The guidance states clearly that the Responsible Person, Authorised Person (Water), all personnel involved in monitoring and maintenance, and relevant members of the Water Safety Group must receive appropriate, documented training. Refresher training is a requirement — not a recommendation — and its frequency should be risk-based.
Responsible Person (Water)
Understanding of legal duties, HTM 04-01, and the WSG framework
As required / when guidance updated
Authorised Person (Water)
Formal AP competency training; HTM 04-01 in depth; risk assessment
Regular refresher; AE-assessed
Estates / maintenance staff
Legionella awareness; monitoring procedures; systems-specific training
Minimum every 2-3 years
Infection Prevention & Control
Water-related infection risk and reporting
As required
Contractors
Demonstrated competence before working on systems
Prior to engagement
Our experience working with NHS trusts across the UK consistently reveals a set of recurring compliance gaps. These are worth reviewing against your own organisation:
Water Safety Plans that are out of date — the schematic no longer reflects the actual system following estates changes.
AP (Water) appointments without formal competency assessment — individuals “acting up” without having been properly assessed and appointed in writing.
No independent AE (Water) — or an AE who is employed by the trust (which undermines independence).
Monitoring records that are incomplete or poorly stored — making it impossible to demonstrate compliance if challenged.
Augmented care areas not specifically addressed in the Water Safety Plan.
Training records that cannot be produced — even where training has been completed.
KEY TAKWAWAYS
HTM 04-01 is the primary guidance document for water safety in NHS and healthcare premises — it goes further than HSE L8.
Every trust needs a Water Safety Group, a Water Safety Plan, a Responsible Person (Water), an AP (Water), and an independent AE (Water).
Risk assessments must be reviewed at least every two years, or sooner following system changes or incidents.
Training is a requirement under HTM 04-01 — not optional — and must be documented and refreshed regularly.
Augmented care areas require enhanced management under Part B of HTM 04-01.
In Scotland, the equivalent guidance is SHTM 04-01.
M&M provide Authorised Person (Water) training, AE (Water) services, and Water Safety Group support for NHS trusts and healthcare organisations across the UK — aligned to both HTM 04-01 and SHTM 04-01.
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M&M Compliance Training Services
Specialists in healthcare technical compliance, AP/AE training, F-Gas certification, HTM compliance, and competence management for NHS and critical infrastructure organisations across the UK.
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