David P wrote:
I am in the UK. Is it generally safe to drink BOILED water from the
hot tap?

If it has been boiled for long enough or at high pressure then it will
be made sterile.You should look into a hot or cold water cystern to get
an idea why it isn't really recommended to drink water that has been in
a header tank unless you really have no other choice.

My hot water comes from a tank or cistern in the loft and this feeds
into a hot water cylinder which is in the house. It doesn't look
wonderful inside that tank in the loft but I reckon if I BOILED the
water then presumably I will kill the germs.

About 5-10 minutes or the addition of a chemical sterilising solution
is generally enough. Water authorities go to great lengths to keep
various nasties out of tapwater and some of them will tolerate fairly
hot water.

Is there another reason why I should not drink boiled water from the
hot tap? Maybe there are dangerous minerals and some other
chemicals found in the hot water system which are unsafe?

Depending on your pipework it may still not be chemically pure to
qualify as potable water. One serious problem in older houses is lead
piping where hot slightly acidic water may dissolve some lead. Not good
to drink! Less of a problem with copper pipes.

Is the caution about this overstated?

Almost certainly, but do you really want to drink water that has been
held nice and warm with a selection of dead spiders, flies, bats,
rodents and other loft inhabitants in it?

BTW - my reasons for wanting to do this is detailed below.

Thanks
Dave

Why? I like to hand wash my dishes in very hot water. My hot tap
does not give me water which is quite hot enough. So I fill the
kettle from the hot tap and heat that water up.

While the dishes soak, I usually think I should make myself a coffee!

Since the energy required to sterilise the gunky water from your hot
tap is way more than that required to boil the purer water from the
cold tap why don't you anticipate your future requirement for a coffee
and boil potable cold water in the first place?

Regards,
Martin Brown