Wow, that seems insanely high. My tapwater hardness is around 75ppm... Are you able to use that water on any of your plants?

While it's not suitable for everyone.
We use catchment here for our domestic water.
We live in a high precipitation location in the middle of the Pacific, far from any contamination sources.
We use rainwater from our rooftop runoff as our water source.
From the roof gutters, it is piped to a 2k gallon catchment tank and stored.
Every time it rains, excess water runs out the tank's overflow.
I've never seen it drop more than a foot or so in the longest, driest periods.

In looking online I see that often people in arid areas also use catchment systems.
Not sure how well that works.
But, it does catch my interest.
I'd be leery of it in metro areas due to air pollution from cars, businesses and industry.
Had never worried about breathing it.
Now that I drink it, I do somewhat.
But, I sure like no water bill or added chemicals, and its being untouched by human hands.

I used to live in mainland northern tier metro areas with treated water piped to my home.
It never bothered my orchids.
And to my knowledge, it never bothered me.
Now that I drink rainwater, it's warm and wet enough that I just put them out on trees in the yard and let it rain on them, beats working at it.

I grew up on O'ahu and my mother in law had places in Kona and Kapoho. Miss home sometimes!

Back to itzi’s original question for a moment, with water of that hardness, the important thing is it’s alkalinity, that is, it’s resistance to pH change upon the addition of acids.

That’s important because high-alkalinity water - pH adjusted or not - will cause your media pH to increase over time, becoming more and more toxic to the plants.

Municipal water reports rarely offer that value, so getting the water tested is a good idea. The J.R.Peters Lab will give you a complete test for $44. Not cheap, but considering out investments in our collection, probably a worthwhile investment.

I collect rain. I mix tap into rain so I don't need to buy calcium supplements. I use my high tds tap water from time to time when I must water and don't have much time. It doesn't seem to bother most Catts, Phals, Paphs, Phrags nor Oncs. The Phrags are in S/H and I flush them thoroughly.