Always double check you've reinstalled all parts for faucets when replacing parts. I forgot that I took one back out. Go downstairs to turn on main. Go back upstairs to washroom. Water is shooting out like a canon hitting the ceiling and covering the washroom in 360 degree spray. No idea how much water, but a few gallons at least.
And this is after trying 4 different stores to attempt to find the right parts for the kitchen sink. Which I wasn't able to find.
Sometimes the tub valve has isolation valves on either side. Looks like a flat head slot. Kinda like this.Probably is. But I was also doing the tub, which doesn't have one. So I turned main off.