30 minutes in standing water is a long time. Additionally, because it is submerged, the water can soak the exterior shell, and find any pinholes of leaks in a waterproof liner.
We left these in for 62 minutes.
You can see the boots are soaked:
Pulled the paper towels out. Dry:
One from the toe area...dry.
Hard to see but interior....dry.
In our opinion, these passed the waterproof test. They already have between 500 and 1000 miles on them, but we sent them out with a 3rd person to get some additional miles on them. They are well liked by all so far. We will post up more later.