"Apparently somebody had left a wrench there when they filled it in 1995," he said. "When they drained it in 2000 the wrench had dissolved."
I dunno, I think if you left a wrench soaking in regular water for five years there wouldn't be much left of it after that either.
During WWII Entire tanks drowned in Siberian sumps and were brought back to life with their engines running.
After five years in regular water I bet the wrench would be in working condition.
I'm not feeling particularly convinced by this anecdote. It sounds a bit urban legendy. Still, I won't claim more than a high-school knowledge of Chemistry so I'm eager for someone to correct me and supply an explanation.
I thought salt and impurities in water was the driving factor in rust.
Once it dissolved a tiny bit of the metal it would no longer be so pure. So this sentence makes no sense. It takes just a minuscule amount of mineral to replicate regular well-water.
It has to do with the economics of water treatment. If you supply water you're incentivised to supply it at the lowest acceptable level of treatment. That's because people just want plain old water, and they don't want to pay a lot for it.
> water mains pipes last longer if its delivering hard water compared to soft water
This is the one thing that may actually be true, but it's because the minerals in the hard water build up on the inside of the pipes over time, creating a protective layer. This is especially great for lead pipes, as it can prevent the lead from leeching into the water.
I've often wondered why dont we have more pure water pumped through the water mains in various countries, and I think after reading about Super K the Japanese Neutrino detector [1] and how the water in the tank was so pure it had dissolved a spanner/wrench that was left in the bottom, years ago, I might have the answer.
Firstly there is health implications for drinking pure water, and whilst it probably wont dissolve your guts [2], it will drastically and quickly alter your chemistry [3] which in moderate doses may be a good way to calm down, I havent tried personally yet, but there is another problem.
The ultra pure water would probably dissolve the older ceramic and metal pipes used to deliver water around the countryside, from the inside out.
In fact I would even go so far to guess that water mains pipes last longer if its delivering hard water compared to soft water, and probably explains the pub culture as the water is standardised in various alcohol brands.
Either way I prefer soft water, its more relaxing and could well help to reduce a certain amount of anxiety in the population along with stress levels, that could be useful for built up cities, but watch the GDP levels of the region go down if that happened and the profile of crimes change [5], not to mention health conditions!
[1] https://www.businessinsider.com/super-kamiokande-neutrino-de...
[2] http://physicsandphysicists.blogspot.com/2018/06/super-kamio...
[3] https://chemistry.stackexchange.com/questions/30754/effect-o...
[4] https://nuscimagazine.com/water-so-pure-it-will-kill-you-261...
[5] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7576670/#:~:tex....