The Collaborative International Dictionary of English v.0.48:

Seepage \Seep"age\, or Sipage \Sip"age\, n.
   Water that seeped or oozed through a porous soil. [Scot. & U.
   S.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sipage \Sip"age\, n.
   See Seepage. [Scot. & U.S.]
   [1913 Webster]