D.M. Procida wrote:
Our downstairs toilet seems to half-empty itself after flushing. I am
sure it never did this before. You can flush it, it seems normal, and
half an hour later the level in the bowl has dropped by a few
centimetres.

What could be going on? There's nowhere for it to go other than escaping
by climbing over the U-bend, and no sign of any leak. I am pretty sure
that no-one in the household is siphoning it away or drinking it.

Daniele

Usually means its about to block. Now is the time to use some
checmicals to dissolve some of the blockage - much harder to do once it
has blocked.

Caustic soda
Sulphuric acid
but not together!

NT