I once thought this and asked the question on here a couple of years back.
I wondered about some of the major and minor elements within tap water. i.e. copper (we had new pipes at the time) which is deadly to many invertibrates, sodium (in water softeners is bad for people and many organisms)
Obviously trace elements such as the high levels of calcium and magnesium have to go somewhere, let alone chlorine and floride (are they trapped in the syrup, or completely blown off when heated!?!)... there are chemicals in water that are there to kill organisms.
The guys here also said there were no concerns.
However, if you give a dog a bowl of tap water and a bowl of rainwater, it will generally drink the rain water.
If you give a dog tap water, rainwater and reverse osmosis water, the dog will generally drink RO water.
even though there were no concerns with tap water, I have continued to use RO water for making syrup. it may not be necessary, but it makes ME happy and the bees don't seem to have a problem with it!
Even though Tim and Broandy obviously find the question highly amusing, I don't think it's that daft a question. People would also think the same as a dog (dogs are not fussy as they drink toilet water, but not many people would think why, even when the dog bowl is covered in slobber and has been left out all day!... ignorance is bliss!).
There is no such thing as a stupid question, just a stupid answer and I think Tim and Broandy have hit the spot with their interesting, informative and valuable contribution!
Is it just because of availablity\convenience that they take water from nasty places and result in gut disorders?
every human in the world can drink fresh and clean drinking water... many however cannot justify walking hundreds of miles to get it and would rather drink from a ditch