Are you expecting a developer to test everything every time they commit? Thoroughly testing even a small application or feature subset will take up quite a bit of time. You also want devs to commit often, so it is easy to roll back an approach that didn’t pan out, or just to go back and figure out what change caused something to stop working. If you end up committing only a few times per week because everything needs to be thoroughly tested, I’m not convinced it is a good approach.
There is a difference between contaminated water, like in Fukushima, and regular non-contaminated cooling water. There should be no radioactive contaminants in the water that the French nuclear power plants release.