Warm water supply and colonisation with Pseudomonas

Question

Dear experts,

From autumn we would like to move to a new apartment with our five year old son. Up to now the course of his disease has been rather mild, apart from occasional (2-3) cross colonisations with Staphylococcus aureus and Haemophilus influenza, which however did not show any symptoms. He did not have PA so far. With regard to the lungs our kid is inconspicuous, the frequency of infection is normal to low.

So far our hygiene “catalogue” comprises the general proceeding and have tried to lead a life free of hystery: in the mornings we let the water run a while from the tap, we keep the toilet lid closed, we wash our hands regularly and stay away from standing waters.

In our new apartment there will be no tankless instantaneous water heater for the water that we use like we had before, but an 80 litre boiler in the basement, which provides kitchen and bathroom with hot water (about 6 years old).
For us it is concrete the question now, if we could life with such a boiler and which measures we have to take (which temperatures in the boiler? Constantly or only at certain times, about 3 times a week?), inorder to avoid the flow-rate with Pseudomonas. Or however, to give up the plan to move in this appartement as a last consequence....
Many thanks for your information (please as soon as possible as the leasing contract should be signed until the end of july).

Answer

Dear questioner,
the German association of gas and water field (DVGW) has prepared a working sheet number W552 to your question. According to this the boiler should be heated once a month to 70°C in order to avoid infections with legionella. Otherwise the temperature should be 60°C. This precautions I would also recommend concerning Pseudomonas aeruginosa.
I hope to have helped you furhter with this,
yours sincerely,
Yours Prof. Gerd Döring

04.10.2010