Responsibility usually depends on where the blockage is and which properties the pipe serves. The owner or occupier is commonly responsible for private drainage within the property boundary, while a water company may be responsible for some shared sewers and public sewers.
Private drains
A pipe serving only one property is generally the responsibility of that property owner until it connects to a public sewer, although leases and property arrangements can affect who organises and pays for work.
Shared drainage
Some pipes serve more than one property. In England and Wales, many shared sewers transferred to water-company responsibility in 2011, but the exact layout and classification still matter.
Landlords and tenants
Responsibility can depend on the cause, tenancy agreement and maintenance obligations. Tenants should report the problem promptly and avoid arranging major work without the appropriate permission.