Our house was built in the early 70s and has a twin pipe system for rain water & sewerage.
We've a problem with the system backing up periodically that can be cleared by rodding with a rubber disk on a drain rod down a vent pipe that's situated between an inspection chamber in the drive and the main sewer in the road.
After rodding there is always some "water" visible down at the bottom of the vent pipe. Would I be right in thinking that there's some sort of bend/trap in the system at that point?
If there normally *isn't*, should I be able to rod through from the inspection chamber right past this vent pipe position towards the road?
It's not a major problem but clearly something isn't quite right and if there's anything I can do with drain rods rather than digging 6' down through the driveway I'd be interested to hear.
Tim