I’ve been having problems with one toilet in my 60 year old house.  I pulled out the original toilet because it was leaking around the base and rotted out the subfloor.  It was in pretty messy shape, and I didn’t want to clean it up, so I bought a new low-flow toilet to replace it.  I replaced the rotted subfloor and installed the new toilet a couple years ago. Well, I ignored it and it eventually worked itself a little loose, and started leaking, so I replaced the wax ring and re-installed it.

The problem with the toilet is that it just doesn’t work well.   It clogs more often than an identical toilet located elsewhere in the house.  Even when it does flush, there are large bubbles that come up into the bowl just after the handle is pressed to flush.  I have plunged and snaked it (fully extending a 16 foot snake) many times and it still has the bubbling symptom.  The waste pipes are completely accessible from the basement.  They are cast iron, and have pinhole leaks with fluffy white mineral deposits oozing out of them.  The waste pipe from the toilet runs exactly horizontally for about 5-6 feet before it ties into the vertical soil/vent pipe.

I guess my question is if this horizontal run is longer than it should be.  Is it normal?  Or is my problem likely a clogged vent? Should I climb up onto the roof and check the vent?  Snake it?  If the pipes have pinhole leaks with mineral deposits keeping them plugged, do I need to get the pipes replaced, or are they fine as is?  The basement is dirty and unfinished, so I don’t care much about looks.  Or is the problem just the relatively new low-flow toilet?

I’m going to be pulling the toilet out again in a week to install some new vinyl flooring, so I can stick a mirror or something into the pipe to try to inspect it on the inside.  Yuck.

Have any advice for me?

Thanks in advance for your help.

-Dan