Who should pay unblocking costs?

Questioner

Due to work on our terrace, we accidentally stumbled upon a sewer that we didn't know was there. Our neighbours didn't know either. It probably runs from house to house (a thing of the past). A plumber has determined that this pipe is full of all kinds of dirt and that it is only a matter of time before it will become blocked. This is not a toilet pipe. It is a kitchen drain, rain pipe, etc. Who should pay for the unblocking costs? Kind regards

Lawyer

Those who have a right of easement on drainage and those who actually use it will have to share in the costs of maintenance, repair and replacement.