On Sun, 6 Jul 2003 00:55:52 +0100, "a" wrote:

The tree sap that's lying under the tree is creosote, that is what
creosote
is extracted from.

I didnt know that so that may be cause.

It isn't, it's just BigWallop talking ****e yet again.

Creosote is a product of coal tar. Turpentine is distilled from tree
sap.

My money is on a tree root having found a damp pipe joint, then shoved
a tendril into it and levered it open into a big leak. You ought to
fix this, probably by lots more digging ! If you feel like spending
the cash, shoving a video camera down the drain will tell you a lot
more, for little effort.