Are there any sourdough bakeries in your area? Pizza, bread or whatever. If so, ask them for a piece and see how that works out. I think starting with a starter you know has been working well will be good. If that ends up the same way, something might be up. And make sure you feed it enough and regularly. Not that I expect that to be the problem since you’ve had starters before. And they are pretty resilient when they are healthy.
If there’s something about the tap water, bottled water might work better.