Who is responsible for the repair of broken sewer drains when you live in a purchased coucil house.?

It is a communal drain

All houses share the cost equally so if six houses share it each house has to pay one sixth of the cost private or council owned

As I understand it your conservatory under which is the collapsed drain is upstream of the point where your soil system connects into the drain - hence you have no drainage problem.

Since you purchased the house 20 years ago and you built the conservatory 2 or 3 years ago, you were the owner of the property when the conservatory was built. Certain modes of construction apply when buildings are constructed over drains and sewers - like the drains must be spanned by reinforced concrete slabs in order to protect those drains from such a thing as collapse. If your work has brought about this damage, I regret to suggest that you are the one who must put it right.

Suggest you check with the Land Registry office and your solicitor.

The question is, who do the sewers belong to? It may well still belong to the council so you need to establish exactly what you bought and what you are responsible for.

Hypothetically, if you closed off the sewer upstream of your property, would the council have to re-route the sewers of the upstream council houses? That would surely be their responsibility. As you are downstream it would not affect you.

Need to find out exactly.

Difficult one to get agreement on but my view is if its on your property but shared then cost of repair should be shared equally between all those whose houses use that sewer pipe. The logic here is that they all benefit from it and must therefore pay towards its repair regardless.

The cost of repairs on a shared drain should be paid for by all who share it.

all who's waste run into the affected run share the bill for the pipework

conservatory not positive but think drains should have been rerouted