I have a bucket in my studio for glaze washing. All dipping containers, tongs brushes etc. get rinsed in there. Having said that, I realize that I wash out my glaze sieves in the laundry sink in my basement.[so some stuff goes down the drain].
The glazes that result from this glaze rinse water are quite beautiful, and have a richness that you cannot get with the pure chemicals from the supplier. I have a Korean celadon type glaze, and a blackish, oilspot Temmoku. Of course I test these glazes before applying them to my pots. They don't usually run, but can be butt ugly occasionally. Then they get relegated to the back corner of the studio with the label; "Don't Use."
The really good slop glazes get used all the time, but then you cannot repeat the results when the bucket is empty.