Public health initiatives designed to reduce the risk of disease or illness in one area of the community sometimes have the potential to increase it in another.

In 2005, there was an outbreak of Legionnaires’ disease (LD) in Christchurch, New Zealand.1,2 In an attempt to prevent further cases of LD, New Zealand health authorities advised householders to check that their domestic hot water systems were set at or above 60°C,1 even though domestic hot water sources were not implicated as contributing to the outbreak.

Subsequent advice that a tempering device could be necessary to cool water before it reached the taps was non-specific (there was no indication of a desirable or safe temperature provided) and unlikely to be implemented (on account of the cost and inconvenience of connecting such a device). Nor was it mandated by legislation.

Data obtained from Christchurch Hospital, Middlemore Hospital (Auckland), and the Royal Women and Children’s Hospital (Adelaide) from 1997–2007 identified 437 children with hot tap water scalds severe enough to require hospital admission, representing 15.8% of the total childhood burns for those hospitals. During the same period there were no cases of LD in children under 20 years of age.

This raises the question as to whether moves to increase the temperature of domestic hot water has the potential to increase the risk of serious scald injuries in children, and whether that risk outweighs the risk of acquiring Legionella pneumonia from domestic sources if domestic hot water exceeds the maximum safe temperature for children, 48.9°C. This temperature also happens to be the temperature recognised by the International Plumbing Code benchmark standard for scald safety.3

The skin of children is significantly thinner than that of the adult (ratio 0.72)3 and more vulnerable to thermal injury. For example, at 60°C, complete epidermal necrosis takes 5 seconds in an adult but only 1 second in a child. Yet there is some evidence that the temperature of domestic hot water in several parts of New Zealand is well over the recommended temperature, and ranges between 64–67.8°C.5

Is this a well-intentioned but misguided initiative that has the potential to put the health of our children at greater risk?

Spencer Beasley
Clinical Director
Department of Paediatric Surgery, Christchurch Hospital
Christchurch
(Spencer.beasley@cdhb.govt.nz)