Hi, I have a drainage problem with my property (it was improperly graded years ago). A previous owner installed a 5" or 6" PVC line 18" below-ground from the problem area in the backyard out to the front of the house (it may dump into the city sewer line or just ends in a dry sump area near the street, in any case it works fine to drain the backyard problem area).

Now I want to break into this line to drain my sump pump water, which currently empties too close to the house and causes ponding in winter. The sump comes out of the house via 1.5" PVC about 15' from this underground PVC line. My question is what's the best method to connect these two lines together?

Should I cut into the 5"/6" PVC and install a Fernco T? (Is a Fernco with stainless clamps OK to use below ground?) Or is there a simpler way to just cut into the top of the 5" line, feed my 1.5" PVC into the whole and caulk around it (after all, it's not under pressure or anything, but I'm wondering if this method is too flimsy or prone to root clogging).

Thanks for any suggestions you may have.

Buy 5" x 1 1/2" PVC "Y" fitting. Cut into your existing 5" PVC pipe. You should cut out about 8" longer piece than length of the fitting. Save this piece. You will need it later. Glue new fitting onto one side of the pipe. Now, use the cut-out piece of pipe to cut what you need on the other end. Insert FlexSeal coupling. Slide it all the way onto the pipe. Glue in the other short piece of pipe. Slide Flex Seal coupling over the cut. Tighten the clamps.

We don't like to use "all rubber" transitional fittings under ground. They flex and give away when you... let's say... drive over them. But I am sure, there are situations where they can be installed w/o too much worry.

Yes, cutting a small hole into 5" PVC, inserting pipe in the opening and caulking it - is something you do not want to do.