I'm on a slab and a septic. The plumbing to the whole house wasn't flowing well at all so several months ago I roto routered the main line and a bunch of roots came out as well as all the backed up s**t. I'm pretty sure the existing pipes are iron and must be rusted or cracked and allowing the roots to grow in, which I'm assuming they will do in the future and cause me more problems. Now I want to move my toilet anyway which just happens to be a 10' straight shot from the septic tank. So my thought was to replace the main line from the tank to the house at the same time as moving the toilet. But there must be tees into the main line at some point for the other drains in the house so I will need to connect to the existing plumbing for the rest of the house. My intention is to run the new line in PVC of equivalent size to the current iron. So my question is what is the best way to connect the pvc to the iron. I was thinking a no hub coupling. Not sure if this is acceptable since this connection will be directly buried under my slab.

Thanks for any help.

Hi JasonShall:

Hey... all sounded good... just need to know that they don't allow TEE fittings underground. All connections underground are made by using WYE fittings or WYE 1/8th COMBINATION fittings (looks like a WYE with a 45 degree fitting in it).

All transition connections between cast iron pipe and new pvc pipe underground need to occur using SHIELDED CLAMPS... see pictures below (No-hub clamps are not acceptable).

4" cast iron is not the same size as 4" pvc... so these clamps account for the different pipe thicknesses.

Best tool for cutting the old cast iron will be by using a sawzall with the NEW lennox DIAMOND blade. They are so new they are actually hard to find, but they cut through 4" cast iron in maybe 5 minutes or less... so they are worth trying to find.

You can also try to use a ratchet snap cutter... they rent these at rental stores (see pic. Below). Just be sure to practice cutting in between important areas of pipe before going for more important lateral line cuts... ;)

The ratchet snap cutter can crush pipe.. so be careful... if find pipe getting crushed a lot then opt for the diamond sawzall blades to make all cuts.

Let me know if need anything else... MARK

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