Posted By Ian stevenson Several staff in my workplace have scolded their hands under the hot water taps in the washroom. This tends to happen when they come in from the cold and do not respond to the high temperature until to late. I have checked the water temperature and it was 58 degrees centigrade. Is there a recomended maximum temperature for hot water in washrooms? I have displayed warning signs until the problem is rectified. Regards Ian

Posted By STEVE Hi Ian I have to agree with Marytn I believe that Legionelle breeds best at tempretures between 20-50 degrees if I remember correctly. I also believe that your system is most probally set at this temp to allow for the winter periods, maybe your water source is some distance away and the travel is suppose to cool it down. Why do your workers just wash their hands under the hot tap can they not mix the water with cold before washing. Do they not understand that hot means hot? I do believe that household taps have a max of 60degrees I will come back tomorrow with more definite advice if some-one has not corrected me in the mean time. Steve

Posted By Nigel Singleton BSc Hi Legionell pneumophila and the 39 other sub groups of Legionella grow best between 25C-45C. Correct thermal disinfection for the species is stated as 5 min purge at 60C+. 58C would be fairly effective but would not guarantee a 100% fatality of the organism. More importantly, Legionella species that survive and are grown at higher temperatures are more dangerous than cultures grown at low temperatures, having the water at 58C could just possibly make Legionella more dangerous if it survives the temperature. There is no reason to maintain hand wash basin temperatures at 58C, in fact this would be wasting a lot of money. The disinfection simply requires a regular purge with 60C+ water to prevent the build up of Legionella. Most humans can stand a temperature of 50-52C for effective hand washing. If your property comes under the umbrella of local council or social services then hand wash basins should be pre-mixed to a maximum of no more then 43C, unless in a catering situation. Mixing hot and cold water in a sink is not a hygienic way of handwashing, perhaps you could look to installing a premix valve to mix cold with hot before it comes out of the tap. This way there is no chance of scalding and hands can be washed under running water, which is the most hygienic method.