drenching

A drenching is when it rains so much that everything gets very wet.

You might hear someone say "The storm gave us a good drenching" after they spent all day indoors while the rain poured outside. This usually means they didn't get out and walk in the rain, but were still soaked up by splashing puddles or running gutters. Sometimes people even use it to describe a fun day at the beach when they got completely wet from playing with waves.