Perhaps I should have said “already have”. I’ll see if I can go back and edit my comment. (Done.)
As sort of an aside; By the use of appropriate programming for appliances, we consistently use around 56% of our total electricity consumption during the Heures Creuses hours. It’s not as much of a reduction in cost as it used to be as the EDF have slowly reduced the difference in price between ‘Heures Plein’ and ‘Heures Creuses’ over recent years. By this means they have increased their revenue without overtly increasing the basic price of electricity. Crafty blighters !
Whilst that part is pretty tight as far as contamination goes, that’s not really where the problem exists as far as testing is concerned from my water test companies. The open ends of shower heads particularly are the high risk points also aerators on taps etc, basically anywhere the aerosol is created. Dead legs of pipe runs are also high risk. We had regular compliance testing and counts were always low however the shower heads themselves harboured colonies of bacteria so used to be soaked in mild acid to dissolve the calcium deposits where it seems most of the bacteria and biofilm proliferated. We had two sets of shower heads that were cleaned and rotated regularly.
Handy to run a high temperature anti legionella occasionally but even that wouldn’t sort out a shower head or tap aerators, with french regs stating max water temperature at the point of delivery at 41c via thermostatic valves it probably makes things worse.
Well I think that any reasonably experienced plumber would not leave ‘dead legs’ of pipe in place. It’s just asking for future trouble when someone drills or nails through a pipe that simply ‘isn’t there’ from the operational point of view.
I agree with your point about shower heads, but anyone with any experience of them having to be replaced due to the little jets becoming blocked will know that it’s a good idea to clean them every once in a while. Soaking overnight in white vinegar works well and is cheap and simple to do.
As for tap aerators, I always take the perishing things out. If I want a reduced flow then I don’t turn the tap on so much. I find that they can become blocked over time and I don’t like the ‘foamy’ flow they produce.
I think that limiting the hot water delivery temperature is a good idea to prevent scalding, and note that any tap providing water at over 50c is supposed to have a warning notice affixed.
Clearly people should take the usual precautions such as running the water through the pipes for a minute or two if one has been away from home on holiday for example, or when returning to a second home that has been unused all winter.
In conclusion, all I can say is that all my life, both in the UK and France, I have always turned the hot water tank temperature down to the minimum needed for reasons of economy, and doing so has never made me sick. I concede that there will always be exceptions in certain special circumstances, but in general, when using mains water in today’s modern age of constant testing, the risk of contracting disease from the water supply is extremely low.
Likewise Robert, I have also turned down the hot water temperature been like that over 5 years but I do run a hot cycle as those working on the water supply and repairs are not always as vigilant as we have seen from dirt coming through the pipes.
Indeed. When the water company fitted a new stopcock out in the street to our supply pipe I had to run the cold tap nearest to the meter for a couple of minutes to flush the dirt out. In fairness, the repair guy did knock the door when he had finished to remind me to carry out said flushing.
I do take your point about dirty shower heads, but upon reflection, a high tank temperature is not going to have much effect on a shower head as no-one is going to take a shower under 50c water. Indeed, the thermostatic shower valves have a safety stop at 38c that one has to manually override if one desires the shower water to be hotter. I don’t think that anyone would want a shower hotter than 40c unless they have asbestos skin. As you said, shower heads should be cleaned from time to time if only to prevent them from becoming clogged.
I think that the risk of contracting Legionnaires is sometimes overly stated. Most people who are exposed to it do not develop the disease. Of course those with pre-existing pulmonary conditions should take more care which includes not sitting by public fountains to cool off on a hot summers day. Apparently the disease can also be acquired from potting mix and compost. At the end of the day it would be very boring to lead a life wrapped in cotton wool while trying to obtain maximum protection from everything.
Thanks for that suggestion and I have checked for a pressure reduction fitting but there is nothing there. I think the hot water pipes have just got clogged so we’ll just have to put up with it for a while