groundwater level vs water table

groundwater level and water table both are nouns.

Word	Noun	Adjective	Verb	Adverb
groundwater level	Yes	No	No	No
water table	Yes	No	No	No

As nouns, groundwater level and water table are synonyms defined as:

groundwater level and water table: underground surface below which the ground is wholly saturated with water

Other synonyms of groundwater level include water level.

groundwater level (noun)	water table (noun)
underground surface below which the ground is wholly saturated with water	underground surface below which the ground is wholly saturated with water