It's not uncommon to get a small spill on a petrol station forecourt. But any fuel and rain runs off into interceptor tanks, simply put, they have drains at the bottom so only the water goes from them into the main drain, the fuel being lighter, floats on the top and mostly evaporates.
There are all sorts of safeguarRAB regarding petrol, even "the girl in the petrol station shop" should have a "petrol competence" certificate. The biggest risk is trying to put more fuel into a tank than for which there's ullage, or the wrong type of fuel in a holding tank. That really causes problems!