Same as mine Few years back my sewerage drain backed up and the lid came off Called welsh water the boys came and unblocked it Took half hour or so as it was blocked next door also Usual suspects are nappies cotton buds and supposedly wipes that you clean the toilet and you can flush shouldn’t be flushed as they don’t disintegrate like toilet paper and cause blockages rolling together forming ball like fat balls Didn’t get charged
So fellas turn up. Firstly, no water there now just debris. ‘Private this mate’. But they got the kit out ‘while they’re here’ and sorted it. No charge. So £20 drink for him and his mate and all cleared They needed the jet washer to clear it, and I suspect it was the flood drain somewhere as they actually cleared it from a neighbouring drain not mine but it’s sorted and we can now wash and dump again!
Old properties tend to run a combined system, newer properties run storm and foul, its not compliant to regs to run foul into storm these days. I would guess yours is not a combined system due to the age of your house, but who knows what goes on underground.
