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Pre-purchase survey leads to turnkey replacement to aid property sale.

WCI was approached to undertake a home buyer drainage survey for the vendor of a property with a presumed failed private drainage system. The sale of the property had fallen through previously due, in part, to the problematic drainage. The foul drainage was found, while providing adequate drainage to the house, to be not functional.  The septic tank was surcharged to a significant level which in turn surcharged the preceding drains. The likely cause of the failure of the system was the undersizing of the septic tank and the connection of surface water to the foul drain.

The connection of surface water means that suspended solids will have systematically been carried through the septic tank into the presumed drainage field causing this to be blinded with solids over a period of time. Notwithstanding the connection of surface water, the undersizing of the septic tank will possibly have contributed to this carry-over too.

The home owner undertook a series of percolation tests in land owned by the property but the porosity was not good. Eventually Brad was able to design a scheme that enabled the proposed new sewage treatment plant to discharge directly to the watercourse by utilising a newly discovered (and tested) discharge pipe.


WCI recommended solution was to install a sewage treatment plant under the driveway and pump treated effluent to the watercourse to the north of the property.  The scheme utilised an existing, previously unknown, discharge pipe from the property to the watercourse. The BS EN 12566:3-2005 certified WPL DMS2 Diamond sewage treatment plant (with separate pump chamber equipped with Lowara DOC7 submersible pump) was specified.

The WPL Diamond is a single tank treatment plant based on an ‘Activated Sludge’ process, one of the most simple and reliable processes available.  Manufactured in high quality GRP fibre-glass, the tank is suitable for installation in all soil types.

The Installation took 4 days start to finish. The system was installed under a Building Control notice and the discharge met the Environment Agency’s General Binding Rules. All the electrical wiring was carried out by qualified electrician with provision of Electrical Completion Certificate.

A final documents pack was sent following the successful installation including:

  • As built drawing showing position of all equipment installed
  • Building Control Completion Certificate
  • Electrical Completion Certificate
  • Full photographic history of the installation
  • All technical drawings and O and Ms of the equipment
  • A service contract offering

If you have any questions about the information presented in this case study, or you would like to talk to us about your off mains drainage options, please contact WCI on 01984 623404 or via the contact form below.

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If you have any questions or just need some clarification on the regulations and how they apply to your property, please call us on 01984 623404