The kitchen faucet in our rental had been leaking before we moved in. There was a fair amount of mold (including the “toxic” mold) on the wall and in the cabinets. The LL had a mold remediation company tear everything out to the studs, even having to shave parts of the studs, then we had to build everything back up again. This was only for the portion against that wall and an adjoining wall. A third wall was left alone.
It took about 2-3 months (we had no kitchen), and cost over $10K. Needless to say, there is no granite, and the cabinets are cheapies from Home Depot (though I’m not complaining, as they work and look just fine).
I’d venture to say water damage is one of the most expensive problems people will ever encounter. Very expensive and miserable work.