or water, subs. (colloquial).Rich for the moment; The state of being FLUSH (q.v.). For synonyms, see WELL BALLASTED.
c. 1696. B. E., A New Dictionary of the Canting Crew, s.v. HIGH TIDE when the Pocket is full of Money.
1725. A New Canting Dictionary
1785. GROSE, A Classical Dictionary of the Vulgar Tongue, s.v.
1823. BADCOCK (Jon Bee), Dictionary of the Turf, etc., s.v. HIGH-TIDEplenty of the possibles; whilst low-water implies empty clies.
UP TO HIGH-WATER MARK, adv. phr. (colloquial).In good condition; a general expression of approval.