Pre & Post Construction Drain Surveys
Establish the condition of your drainage before works begin and verify it again once construction is complete.
We carry out pre and post construction CCTV drainage surveys for developers, contractors and project teams, helping identify existing defects, reduce uncertainty and provide a clear record of drainage condition throughout the project.
When should you arrange a pre or post construction drain survey?
Pre and post construction drainage surveys are useful where building works could affect existing drainage, or where the condition of a drainage network needs to be documented before and after a project. They are commonly carried out:
Before excavation, groundworks or construction begins
Where existing drainage runs through or close to a proposed development
Before piling, foundations or other significant structural works
When taking responsibility for existing drainage infrastructure
To identify defects or restrictions that could affect construction planning
Following new drainage installations or alterations
After construction to identify damage, debris or other issues
Before practical completion, handover or final project sign-off
Where a clear pre-works and post-works condition record is required
Surveys can be commissioned individually or as part of a combined pre and post construction package, depending on the project requirements.
What does a pre & post construction drainage survey include?
The scope of the survey can be tailored around the proposed works, existing drainage layout and level of information required by the project team. Depending on the agreed scope, our surveys can include:
CCTV inspection of accessible foul and surface water drainage
WRc-approved reporting with MSCC5-coded observations
Identification of cracks, fractures, displaced joints, root ingress, deposits and other defects
Recording of existing defects before construction begins
Identification of construction debris, silt, blockages and restrictions
Recording of pipe diameters, materials and flow direction, where these can be established
Identification and recording of manholes, chambers and key drainage assets
Drainage tracing and mapping where required
HD CCTV footage and supporting images
Comparison with the pre-construction condition where both surveys are undertaken
Identification of areas requiring cleaning, repair or further investigation
Recording of access limitations or sections that could not be surveyed
Clear reporting to support project records, handover and sign-off
Where existing drainage information is incomplete or inaccurate, the survey can also be used to help establish the layout of the drainage network before works begin.
Protecting drainage before, during and after construction
Underground drainage can easily be overlooked during construction because much of the network is out of sight.
A pre-construction survey creates a clear record of the drainage system before work starts. This helps the project team understand what is already there, identify defects and restrictions, and highlight drainage assets that may need to be considered during design or construction.
It also provides an important baseline where the condition of the drainage may later need to be reviewed.
Before construction
A pre-construction drainage survey can help:
Establish the existing condition of the drainage network
Identify pre-existing structural or service defects
Confirm drainage routes and connections where required
Highlight assets located within or close to the construction area
Identify restrictions that could affect design or construction
Create a clear condition record before contractors begin work
Identifying these issues at an early stage allows them to be considered as part of the project rather than discovered unexpectedly once construction is underway.
After construction
Construction activity can introduce new risks to a drainage system. Rubble, silt and other debris can enter drainage during the works, while excavation, heavy plant, ground movement or alterations to the system can affect existing pipework. Newly installed drainage can also contain defects or restrictions that are not visible from the surface.
A post-construction CCTV survey allows the drainage network to be inspected following completion of the works and can help:
Identify damage or deterioration following construction
Detect rubble, debris, silt and other restrictions
Check existing drainage within the construction area
Inspect new or altered drainage where included within the scope
Identify standing water, poor flow or other installation concerns
Compare the network against the pre-construction condition
Highlight any cleaning, repairs or further investigation required
Provide drainage information for project completion and handover
Where remedial works are required, a further CCTV inspection can also be carried out once these have been completed to verify the final condition.
Who are pre & post construction drain surveys for?
Our pre and post construction drainage surveys are suitable for organisations that need reliable drainage information before, during or following construction works. We regularly support:
Main contractors and subcontractors
Property developers
Civil engineering companies
Project managers and quantity surveyors
Architects, consultants and design teams
Commercial property owners
Facilities and estate teams
Schools, colleges and healthcare estates
Infrastructure and public-sector projects
The scope can be tailored around a specific construction area, individual drainage system or larger development site depending on the requirements of the project.
How does the survey process work?
We keep pre and post construction drainage surveys structured and straightforward, with the scope agreed around the proposed works.
1. Project information and scope review
We review available drainage plans, the proposed construction works, site constraints and any specific reporting or mapping requirements.
2. Pre-construction CCTV survey
Where a pre-construction survey is required, our engineers inspect the accessible drainage network and record the existing condition, defects and agreed asset information before works begin.
3. Reporting and drainage records
We provide the agreed survey information, which include MSCC5-coding defect schedule, CCTV footage, supporting images, drainage mapping and a clear recommendations.
4. Post-construction inspection
Once the relevant construction works are complete, we return to inspect the agreed drainage network and identify any changes, defects, debris or restrictions.
5. Final reporting and recommendations
Where both surveys have been undertaken, the findings can be reviewed against the pre-construction condition. Any issues requiring cleaning, repair or further investigation are clearly highlighted to support project completion and handover.
Where remedial works are subsequently carried out, we can also complete a final verification survey if required.
Why choose Clearflow Surveys?
Pre and post construction surveys need to provide more than CCTV footage. They should give project teams a clear and reliable record of the drainage system that can be used throughout the construction process.
Clearflow Surveys provides:
WRc-approved reporting with clear identification of structural and service defects
Pre-construction condition records to establish an accurate baseline
Post-construction inspections to identify changes, damage and construction-related issues
Drainage mapping and asset identification where required
HD CCTV footage and supporting images
Clear identification of priority defects and areas requiring further investigation
Practical recommendations for cleaning, repair and remedial works
Flexible survey scopes based around construction programmes and site requirements
Experience working on commercial, healthcare, education and development sites
Clear reporting suitable for contractors, developers, consultants and project teams
Our aim is to provide useful drainage information that helps reduce uncertainty, resolve issues early and support the project through to completion.
Past Projects
Examples of pre- and post- construction drain surveys carried out across the UK.
Pre-construction drain survey at Lister Hospital
Pre and Post construction drain survey at The Joshua Tree
Pre-construction drain survey at a high school in Bolton
Pre-construction drain survey for new clubhouse development in Leeds.
View Project →
Pre-construction drain survey for new clubhouse development in Leeds.
View Project →
Pre-construction drain survey at a high school in Bolton
Need a Pre or Post Construction Drain Survey?
Establish a clear record before construction begins and identify any drainage issues before project completion.