• Septic tank and sewerage system installation in Norfolk
  • Sewage treatment plant maintenance in Norfolk & Suffolk
  • General groundworks and gravel driveways laid in Norfolk

Sewage Treatment Solutions
& Groundworks

in Norfolk & Suffolk

East Anglia's Most Reliable Sewage Treatment System Installer

If you live away from mains services or planning to build a new dwelling or commercial property that requires an efficient effluent system, this now needs to be compliant therefore requires a sewage treatment plant under the new General Building Rules 2015. See Reqirements.

The waste water goes through three chambers within the tank; solids and liquids separate, then the second stage airs the waste encouraging the bacteria to work on the organic matter.

This results in the waste that is left being 95% clean and ready for disposal.

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If you have a septic tank problem or requirement for a new sewage treatment plant installation, contact us for a site inspection and assessment.

Cox Construction can install and provide servicing, commissions and warranty for Marsh and Harlequin products. We are proud to be Marsh Approved Installers.

Frequently asked questions

Some of the common questions we get asked.

1. How long will it take to install a new plant?


A typical installation takes just 2 days, meaning minimal disruption to your household or business.

2. Can I still use the loo during the installation?


Yes, we just ask that you not use the bath or washing machine for one evening.

3. Will anything need to be installed above ground?


There will be a green compressor housing but we will always do our best to disguise this near a bush or hedging.

4. Will there be much mess?


No not usually, although each job is different. We do our best to leave your garden as tidy as possible. You can see examples of our previous works in progress here, and we have many happy customers to testify that we leave things much tidier than expected. We also have the option of using ground protection, matts, and turfing.

Happy customers...

a satisfied customer

Adrian gave us a competitive quote. He came and started on the planned date, and the installation was smooth and efficient. Finally the area was smoothed off and left tidy.

Mrs Smith, Suffolk


Alex installed 100 pot plant at our site, perfect job! we had no worries the whole time. Alex and Ozzy were both great guys and they got the job done quickly and stress free.

Kieran E, Norfolk


Alex Cox saved me £5000. I didn't trust the company that quoted me for a new soakaway under my flooded driveway. So I asked around and hired Alex on recommendation. He quickly found the source of the problem, cleared two hidden drains and the pipe work to an old wet drainage system and installed two new manholes and a third gully.

Alan T, Norfolk

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