I test all my brushes to the extreme, they are completely submerged for 10 to 15 minutes before I use them, they are dumped into a big bowl of hot water, sometimes a safety razor takes a swim with them. There is no need for you to do that, water will dull the shine of your brush and will start to causes deterioration on wood with a low density, especially on the thinner parts like the rim where the knot is mounted, more so if you don't dry your gear after use.
The problem with soaking your brush in a lathering bowl is that many brushes will roll into (or fall out of) the bowl if you try and balance them in some way with the handle part outside the water.
Here are two small stainless steel bowls that are small enough to have the handle sit outside the water while the knots soaks away happily in the warm H2O. The small one works good for short brushes and the larger one for the longer ones. The small cup stands 52 mm high, and the larger ones 61 mm. We are a water scarce country, so this little bowl makes lots of sense for this reason also.