PDAS Mapping

Private Drains and Sewers Act 2011

What is PDAS Mapping?

CALM have been involved in a number of projects incorporating the investigation of previously unmapped assets, such as with PDaS areas (Private Drains and Sewers) which until 2011 were not recorded by water companies.

Surveying and delivering quality verified data for such projects enables the asset owner to establish current conditions, locate and resolve any immediate issues and plan for remedial actions.


  • Any major defects that are found, such as collapses or anything that would cause a blockage – are reported to the client directly from site, enabling the client to respond quicker and reduce the risk of any incidents
  • On occasions our site teams locate properties where a foul sewer had been connected into a surface water drain, resulting in contamination of a water course. Any cross contamination is reported immediately from site and the sewer would be re-routed to reduce the fouling of the water course
  • Reporting is visible in real time on the PDaS Mapping System and highlighted from site using our mobile apps via an “Issue Log” email notification and back up phone call

We Have Locations Throughout The UK