Many operators do not realise they should be aware of the type, location and routing of site drainage.  Most sites consist of two types of drainage; “surface water” and “foul”.

Surface water drains usually lead to a watercourse or soak-away and so should carry only clean, uncontaminated rainwater from roofs and clean yard areas.  Even so, under some circumstances, some treatment of the water may be required.  Foul drains are expected to carry contaminated water, trade effluent and domestic sewerage to a treatment works.

It is common for drains to be connected wrongly through error or ignorance and it is essential that the site operator is fully aware of the purpose and routing of all drains and gullies.  All drainage systems should be maintained in good working order and the Environment Agency Pollution Prevention Guideline PPG11 states that a programme of regular inspections should be established.  PPG11 also recommends that gullies, grids and manhole covers are colour coded to aid identification.

As a general rule the local sewerage undertaker is responsible for foul water drains and sewers.  They will have clearly laid down rules for the contamination levels within any discharge and specific consents will be required should any of these limits be liable to be exceeded.  It is the responsibility of the operator to establish these levels with the local sewerage undertaker.  It is possible that on some sites, oily water separators will be installed in foul water drainage systems and may also be a requirement of the sewerage company.  Sources of dirty water such as sinks and toilets must be connected to the foul water system and nearest drain.

The Andel-PPL drain survey report can be tailored to suit a client’s requirements and budget.  Wherever possible, the report will identify which drain performs which function and the route of each drain will be traced and mapped onto a site plan.  On larger, older sites where no plans are available it will be a time consuming and difficult task to trace and identify every drain and its ultimate discharge/connection point.

Where budgets are limited, PPL can help the client prioritise the work to higher risk areas but, under all circumstances, once the drainage system is reported and mapped records will be kept by PPL for access by the client at any time in the future.

The Andel-PPL report will detail any evident problems and recommend cleaning or other further action as required.

Our survey includes the following:

·    Gullies and manholes connection and general information.
·    Levels and sizes of the interconnecting pipe work.
·    Details of surface/foul water discharges to public combined sewers.
·    Invert levels of the public sewers and where they leave the site.

In order to carry out the above, the survey will include:

·    Lifting all manhole covers and access to inspection chambers.
·    Identify location of foul, surface water and combined sewers and drains.
·    Identify chamber locations and assign them unique numbers; highlighting them on a suitable drainage plan.
·    Complete a manhole survey sheet for each manhole.
·    Dye test.
·    CCTV survey (if necessary).

Upon completion we will provide:

·    An updated drawing showing manholes, chambers and gullies with unique reference number in both paper and electronic format.
·    Photographs of the chambers with any defects/damage in both paper and electronic format.
·    Completed manhole survey sheets for each chamber.

 Andel-PPL Drain Tracing (244.88 kB)