Why is my toilet leaking there?

If it's clean water start looking higher up, from the cistern . trace the outlines with your hand or with paper.
If it's a low level system , where the flush pipe joins the pan at the back , check the rubber bung and make sure the pipe doesn't move in or out. Also check if the leak is from the down pipe out of the cistern base.
If the cistern is sitting ontop of the pan, close couple type, check the area at the back incase the 'doughnut ' ring is perished. This is the seal between the cistern and the pan.
Lastly, it could be from the pan outlet pipe as it joins the plastic pipe to the sewage system. Older pans that have an S type vertical outlet may be cracked, in that case you will need a new pan.

Maximo
July 2008

......or the connection where the toilet pan connects to the waste pipe.

John
July 2008

i doubt if it is the base of toilet.more likely where cistern meets the toilet itself.if so will require splitting + resealing.
check by drying all the toilet with dry towel. then use colored toilet paper to detect any leak (colored paper easily shows wet)

plumbob
July 2008