His chops watered at it; he longed earnestly for it. To watch his waters; to keep a strict watch on any one’s actions. In hot water: in trouble, engaged in disputes.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
water sneaksman * water bewitchedNathan Bailey's 1721 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes