Water safety in NHS and private healthcare facilities is governed by the Department of Health's Health Technical Memorandum 04-01, known as HTM 04-01. This technical memorandum builds on the foundation of ACOP L8 but introduces significantly more stringent requirements designed to protect highly vulnerable, immunocompromised patients from waterborne pathogens including Legionella pneumophila and pseudomonas aeruginosa. HTM 04-01 requires healthcare organisations to establish a Water Safety Group (WSG) comprising the dutyholder, a designated responsible person for water, the estates director, infection prevention and control leads, and an independent Authorising Engineer for Water (AE(W)). The Water Safety Group is responsible for approving the organisation's Water Safety Plan (WSP), reviewing monitoring data, and making decisions about the management of waterborne infection risks. Unlike commercial buildings, healthcare facilities must manage pseudomonas aeruginosa as well as Legionella. Pseudomonas colonises the last two metres of pipework and outlet fittings and poses a direct infection risk to patients in augmented care units including intensive care, neonatal, and oncology wards. Management strategies include enhanced microbiological sampling at augmented care outlets, aggressive outlet hygiene programmes, and the use of 0.2-micron point-of-use filters as a temporary control measure during periods of elevated risk. Temperature management is critical throughout: HTM 04-01 requires hot water to be stored at 60°C and distributed at 55°C or above, with monitoring at sentinel outlets at defined frequencies. Cold water must be maintained below 20°C at all points of use. Compliance with HTM 04-01 requires specialist knowledge. Generalist contractors often lack the clinical understanding necessary to operate safely in healthcare environments and interpret patient risk appropriately.