Same. My area is built into limestone. My toilets get crusty after a couple days.

I’m about to install a polyphosphate water softener cartridge before the whole house filters, to combat this. My pipes and appliances are scaled no doubt; I get a ton of sediment in my faucets.

Polyphosphate supposedly not only softens water but also descales everything it runs through over time, and it lasts a long time. (I plan to just refill the cartridge when it runs low, so it’ll be fairly cheap long term compared to a salt softener, and it’s the size of a standard single stage filter). Fortunately all the pipes in my house are copper, except the ones leading in which are lead but won’t be impacted by the anti-scale (and just in case I use a reverse osmosis unit for all consumed water, the water here tastes like shit so…)