water gage vs water gauge

water gage and water gauge both are nouns.

Word	Noun	Adjective	Verb	Adverb
water gage	Yes	No	No	No
water gauge	Yes	No	No	No

As nouns, water gage and water gauge are synonyms defined as:

water gage and water gauge: gauge for indicating the level of water in e.g. a tank or boiler or reservoir

Other synonyms of water gage include water glass.

water gage (noun)	water gauge (noun)
gauge for indicating the level of water in e.g. a tank or boiler or reservoir	gauge for indicating the level of water in e.g. a tank or boiler or reservoir