"Andy Pandy" wrote in message
...



However I also confirmed it by putting a hose down the downpipe and
noting it didn't appear in the sewer ! I tried to get hold of some
drain dye but without success. One plumbers merchant suggested
emulsion paint but that didn't seem a good idea.

Fluorescein's the stuff to use, from chemical suppliers. It's not expensive
and you don't need much.

Mary