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Sometimes when looking at a new project a various amount of site investigations needs to be undertaken, however the first step is to undergo one of our Septic Tank compliance checks. This will aid in highlighting any potential issues and what further steps need to be undertaken.

We recently attended a 4-bedroom property in North Yorkshire which occasionally also acted as a wedding venue, the unit that was installed was a circa 1,650 litres twin stage septic tank which immediately raised concerns as this would not comply with the General Binding Rules (Rule 10).

During this inspection we arrange for the septic tank to undergo a full desludge, this allowed us to check the internal structure and pipework, the primary chamber had a visible crust with evidence of solids and a buildup of earth and soil becoming evident in the secondary chamber. A number of the internal ‘T’ pieces had also come away.

The final point of concern raised during the inspection was that we were unable to clarify for definite where the point of discharge was to, it was assumed that this would go to a drainage field however at a nearby pond we did find some pipework discharging in it.

To ensure that the right avenue was pursued we were also required to carry further investigations, this included a full comprehensive CCTV survey. As the system had already been deemed non-compliant with the 2020 General Binding Rules, the existing pipework needed to be checked to see what needed replacing and what goes where.

The results of this indicated a few points which needed to be addressed as part of the installation process, surface water was identified to be connected to the foul drainage and vice versa as a foul gulley which took the kitchen waste was connected directly to the surface water network.

Unfortunately, the location of the outfall was no clearer as the CCTV unit was unable to fully camera the run at the time, root ingress had blocked and dislodged the pipework meaning to fully ascertain this we would need a root cutter on site and high-pressure jetting before we could clarify the exact route.

The survey did however confirm that the toilets that historically were no longer in use and not connected to the foul drainage therefore did not need to be considered into the sizing calculation, the venue hired in specialist welfare units to cover any events.

Due to the nature of the existing pipework being beyond repair we opted to quote for a completely new installation including outfall pipework.

We proposed to install a new Klargester Bioficient 1 IPS package sewage treatment plant to serve the 4-bedroom property, the pumped outfall lifted the treated effluent via a 50mm MDPE pipework before a new outlet sample point was installed with a short section of 110mm pipework to the new outfall location.

Due to the wide array of damaged pipework and surface water cross connections we were required to install a total of 49 metres of new gravity inlet drainage from the property to the new system. We also installed a total of 13 metres of new 110mm surface water drainage to eliminate any contamination.

As part of our installation process, all works we undertake are carried out under a Building notice. During an inspection from the building control officer, they advised in order to sign off the work and issue the completion certificate they needed an additional length of pipework installed include a non-return valve at the point of discharge.

Ultimately the final installation was designed in compliance with the General Binding Rules and Building control Part H guidelines.