it was pretty noticeable to me. i don't think it's the groundwater specifically but they started treating the water with chlorine as part of the change, which you can definitely taste. i installed a filter under the sink and at least that fixed the problem for me... but it did make me reflect on what's in our water, in general.
I swear that SF water started tasting worse after they started adding groundwater a few years ago:
https://www.nbcbayarea.com/news/local/san-francisco-new-sour...