• 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


The installation work was carried out satisfactorily with any disruption to the garden put back in good order. We had good support for some problems prior to the installation which was much appreciated.

Chris M


Great company, first class service, always go above and beyond the call of duty. Highly recommended.

Leon, Norfolk

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