Responsibility of your Drainage
The individual Wirral house holder is usually responsible for their private drainage lines, within the boundaries of their own property.
Prior to 2011 the householder used to be responsible for the whole drainage system up to where it joined the public sewer but things changed a few years ago.
The Government, in 2011, transferred ownership of most of the private sewers in England and Wales over to the water and sewerage companies, to form part of the public sewer network.
In some circumstances this can become confusing and the Guide to Transfer of Private Sewers - Regulations 2011 explains things in more detail.
Your local Utility company; United Utilities (for NorthWest England), Welsh Water (for North Wales) or your Local Council Technical Services Department could all help you determine who is responsible for your drainage system.