I guess it's all about the temp it's stored at, and the length of time it's stored for. I use my DHW all the time in the kitchen but then mine is a mains pressure system in a SS Solar thermal cylinder.

Yes it would have to be only when solar was available. I wondering what the health risks are?
temperature wise, out the tap its currently 60. immersions stats are up to the max and supplied only ever by Pv dump. back up is gas primary circuit set at 50
2x120 Tanks, probably alway use one per day so storage is never more than 24hrs

For me it depends upon whether or not the cold storage tank is closed sealed. I have seen many open cold supply tank that had no or very flimsy covers so no way to keep out mice and birds or other unwanted dirt to contaminate the water (including up the overflow pipe)

Posted By: jamesingramIve always considered it a no no to use the headed cold water tank supply thats then heated in the hot water storage cylinder for hot drinks or cooking , boiling veg etc.

As Ive now pretty good supply of constant hot water via PV heated HW storage I'm wondering again if filling my veg steamer etc with mains cold tap water is really necessary and missing an energy saving trick .
Its being boiled isnt it , What are the other negatives involved ?

Yes, me too. Or at least in our previous houses. But now we don't have a cold water tank, and we don't have a hot water cylinder either. For all the good reasons that you state. All the water we drink, cook with or shower in is fresh from the mains, as is the water we flush the loo with.

But it is all softened, because we live in a hard water area. Hot water is passed through a PHE and heated from our thermal store. Until very recently my wife has insisted on using 'filtered' water in the steamer, but I have finally persuaded her to try using whatever comes out of the hot tap. 'Filtered' is raw tap water that has been through a couple of filters to soften it and strip the heavy metals etc, which is overkill for a steamer IMHO, although I'm prepared to use it for the kettle.

We would never fill the steamer with raw tap water because it would scale up so quickly. But I'd fill it with pretty much any softened water, even if it had been stored, since all the veg is going to see is the distilled vapour.

Making tea is much more critical from a taste point of view. Each to his own. Legionella is a respiratory disease; you don't get it from eating or drinking stuff, but from breathing or showering infected vapour/droplets. You don't get it or anything else from washing utensils either, as long as they are dried and ideally left to dry further for a while first.

Washing and drying surfaces/utensils is sadly not sufficient to remove pathogens that are present in the washing up bowl, or dissolved materials. So, we're all regularly exposed to whatever contaminants may be lurking in our domestic hot water supply, and generally it's safe and we don't get ill from them, the food is more risky than the hot water!

However commercial kitchens are supposed to use a "2-stage cleaning" regime where the washing/drying is reinforced with a disinfectant or steriliser stage. (Cumulative risk tolerability, again, as you learn while taking your Food Safety certificate to help at a street party!).

https://www.aberdeencity.gov.uk/services/environment/food-hygiene-guide#2146

https://www.sciencedirect.com/science/article/abs/pii/S0168160502005408


Steaming food is pretty safe because of the temperatures, but even distilling doesn't produce 'pure' water - the lively bubbles in the boiling water, throw up lots of tiny droplets of the contaminated water into an aerosol mist which drifts along with the steam. Any VOCs end up in the steam too. Again, it's a question of how safe you really want to be, but it does take some extra steps if you need to produce really pure water, say for industrial/laboratory uses.

I presume the hot water tank is stainless steel not copper. Personally would not use water out of a copper tank for the same reasons as people gave up cooking in copper pans.

>I have seen dead birds in feed tanks

Fawlty Towers covered it quite well!

https://m.facebook.com/50shadesoffun1/videos/fawlty-towers-pigs-and-pigeons/465008930666637/