storm drain vs stormwater drain

storm drain and stormwater drain both are nouns.

Word	Noun	Adjective	Verb	Adverb
storm drain	Yes	No	No	No
stormwater drain	Yes	No	No	No

As nouns, storm drain and stormwater drain are synonyms defined as:

storm drain and stormwater drain: a system of watercourses or drains for carrying off excess water

Other synonyms of storm drain include drain system, drainage well, storm sewer.

storm drain (noun)	stormwater drain (noun)
a system of watercourses or drains for carrying off excess water	a system of watercourses or drains for carrying off excess water