seepage
Concise Oxford English Dictionary © 2008 Oxford University Press:
seep/siːp/
▶verb (of a liquid) flow or leak slowly through porous material or small holes. ▶noun N. Amer. a place where petroleum or water seeps out of the ground.
– derivatives
seepage noun.
seepage noun.
– origin C18: perh. a dial. form of OE sīpian ‘to soak’.
'seepage' also found in these Oxford entries:

