To drench something or someone means to make them completely wet.
They turned fire hoses on the people and drenched them. [VERB noun]
They were getting drenched by icy water. [get VERB-ed]
We were completely drenched and cold. [VERB-ed]
I reached Kilmarnock in the early morning in drenching rain. [VERB-ing]
Synonyms: soak, flood, wet, duck