Hi, my toilet clog a lot lately even if you flush it with no solid waste in it. I replaced the toilet but that did not help I was thinking perhaps there was not enough pressure from the water in the closet to force the waste into the stack. A friend of mine said that the line was made of cast iron and that over a long period the inside of the line gets rusty and shrinks due to its age of and that little bits of toilet paper and waste are sticking to the sides of the pipe due to the scaling on the inside and eventually clogs the pipe. I have to snake it every couple of days could he be right.

Thanks

Bob

Toilets use a combination of gravity and siphon action to empty the bowl. No pressure is involved. Most older cast iron systems are 4" although some are 3" pipes and do not shrink. The flange usually makes a quick 90 degree turn in the floor and hits the stack within a couple of feet. The horizontal runs are generally where the problems occur. What did you notice when you replaced the toilet? Has your system been altered since it was originally built? Problems can arise when pipe is pitched too steep that the liquids flow fast and the solids are left behind. It is true, there can be build-up in the pipes. If your vent is clogged, your toilet will back up. Sometimes the only way to get at it is to drop a big piece of chain down from the opening in your roof (kind of like the poor man's chimney sweep). I hope this helps.

What floor is the toilet on and are any other fixtures having issues?

Sounds like a clog, cast Iron does degrade and gets very rough on the inside. Should consider augering all the way to the street. Another reason cast iron is not used today.