Sure, that all makes sense, but it's still anecdotal.

I'm not a chemist, but "combined chlorine" from what I read is also known as "Chloramine". Going from there, I went to both Minneapolis and St Paul's water supply. I couldn't fine chloramine levels for St Paul but Minneapolis does have it, and it's listed at 3.9ppm.

Minneapolis Jan 2024 Report

Now, knowing that, I went to the EPA to figure out what a safe level was, and turns out they have an entire page about this mostly due to fear mongering and misinformation. In fact they have a blurb describing exactly what you're talking about:

Many public water systems (PWSs) use chlorine as their primary disinfectant. However, some PWSs changed their secondary disinfectant to chloramines to meet disinfection byproduct requirements. Since then, consumers have raised questions about this switch in disinfection.

From the EPA's basic information site, The drinking water standard for chloramines is 4 parts per million (ppm) measured as an annual average.

Full EPA Link.

They also included a full scientific study on how it affects us, if you're good with it I'd suggest reading up.

It also looks like the EPA and most cities started doing this back in the 1930s, so this is not a new thing Minneapolis just started doing, it's actually been standard practice for a while.

By pure luck you got someone who's SO worked for years making pool testing kits, and I asked them about this. They said:

Sure, it can be an issue, and what they're saying is true, but the combined chlorine isn't really the issue. The bigger worry is that it easily binds to create carcinogens, so they check regularly to make sure both levels are low. We had machines that had automated sensors monitoring both to make sure they stayed in safe levels, it's very regulated at the municipal level.

If this is what you meant by "impurities", then yes, they track carcinogens extremely closely. They also have automated testers constantly running verifying that the water that passes through is safe.

Both St Paul and Minneapolis post their carcinogen numbers, and they are both well within safety parameters.

So, again, I am not a chemist, but this is one of those things that I have extreme skepticism on when someone says we don't have safe tap water. Our tap water is one of the only things I trust about governments because I know what happens when it doesn't work, and when it doesn't work we really know it doesn't work.

And hey, even if it is flying under the radar, you can buy kits to test them, my SO confirmed it's a pretty standard test and would show as failed immediately. If it did fail, from what I've read and what my SO tells me, you wouldn't be here, you wouldn't just be drinking bottled water, you'd be going to the press about it.

So, this stuff sounds really scary when you first read it. Hell, when I read what you said my stomach dropped, but then I thought "wait a minute, let's find out for sure". And by reading into it, I found out a lot of neat information and learned more about water treatment. So my main take away is that we need to stop believing what our friend told us and listen to the actual scientists. Things like water treatment sound really scary when we don't understand that science behind it, but that's the cool thing, we can let them. Passing on information we haven't vetted ourselves is a dangerous thing as we've learned over the last few years. It's on us to go personally validate if what we hear is true.