In article ,
Jonathan Sachs wrote:

I used to own a house that was built on a stemwall foundation. I
grounded the electric outlets by drilling a hole up through the bottom
plate under each outlet box, pushing ground wires up through the hole,
and fishing them into the box.

I'm now buying a house that is built on a slab, and many of the
outlets are ungrounded. How should I deal with the problem in this
case?

Eh? What problem?