Browse F.A.Q. Topics

Care & Maintenance

  • Where can spare parts be obtained?

    Original spare parts for the small Diamond package wastewater (sewage) treatment plant are available directly from our network of trusted independent experts or the manufacturer (WCS Environmental Engineering). For further information, please send us an enquiry or contact us on +44 (0) 2392 242 600.

  • Do domestic wastewater (sewage) treatment plants need service and maintenance?

    Yes, all wastewater (sewage) treatment plants will need service and maintenance in order to ensure an efficient and reliable product.

  • What happens if I sell my house after installing a Diamond wastewater (sewage) treatment plant?
    England:  According to the Environment Agency in England, if you sell your property, the new owner must be informed of your wastewater (sewage) treatment plant in writing. The information in your writing must include: a description of the treatment system and drainage system; the location of the main parts of the treatment system, drainage system and discharge point; details of any changes made to the treatment system and drainage system; details of how the treatment system and drainage system should be maintained, and the maintenance manual and records if you have them. Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.

Installation & Design

  • How are domestic wastewater/sewage treatment plants installed?
    Our small Diamond package sewage treatment tanks are designed to sit below ground. The Kiosk can be installed above or below ground dependent on site conditions. A comprehensive installation manual is supplied with each plant, which you should read thoroughly prior to specification and installation. We also recommend that you use an experienced and qualified installer. For further information, please send us an enquiry or contact us on +44 (0) 2392 242 600. Please watch our installation video of the compact, domestic Diamond package wastewater treatment plant.
  • What is a percolation test?

    A percolation test is required for a drainage field to assess how much water can drain away through the subsoil.  This is performed by an experienced site surveyor who excavates a small area of subsoil to monitor.  We advise this test is taken prior to a package sewage treatment plant being installed.

  • How will I know if I have a high water table area?

    This can be determined by digging a trial hole and leaving it open for 48 hours for a site assessment. If you would like to request a visit from an independent expert in order to carry out this assessment, please make an enquiry or contact us on +44 (0)23 92242 600. 

    Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.

  • When to use External Pump Chamber (EPC)

    If the location of the Diamond plant is on an incline, in a highwater table area or a long distance away from the designated discharge point (ie: soakaway/water course/ditch) the final effluent may require pumping. The Diamond range can be specified with an EPC which can deliver up to 100 litres per minute of effluent at a head of 4m. The external pump chamber (EPC) can be simply retro-fitted and is easy to maintain.

  • What is the British Water Code of Practice for Flows and Loads?

    Flows and Loads is the Sizing Criteria, Treatment Capacity for Small Package Sewage Treatment Plants. This code of practice was prepared by the British Water Package Sewage Treatment Plant Focus Group comprising manufacturers, suppliers and service companies of all types of small wastewater treatment systems.

    Loading tables:

    This code of practice provides a table of loadings which allows the total daily sewage load from properties to be calculated and it is recommended that all designers should use this table when sizing and designing non-mains sewage treatment systems. The flows and loads values given represent current best knowledge within the UK but may change with time in line with per capita water use.


    The Diamond wastewater (sewage) treatment range is designed using the British Water code of practice flows and loads, to ensure the tank is sized correctly.


  • How long does it take for a wastewater (sewage) treatment plant to start working?

    Your newly installed wastewater (sewage) treatment plant can be used immediately! The biological process can take between 6-8 weeks to start working.

  • Where can I discharge to?

    The treated final effluent from your package sewage treatment plant can be discharged in to a water course or a drainage field with Environmental Agency approval.

    Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.

    The high quality Diamond range is CE marked, fully type tested and certificated in accordance with the mandatory European standard BS EN12566-3 2014 for small wastewater treatment systems.  Performance tested at an independent accredited facility in Aachen, Germany by PIA Institute for Wastewater Technology.

Regulations & Approvals

  • Is approval required to install a small domestic wastewater (sewage) treatment plant?
    General binding rules state that your small wastewater (sewage) treatment system must meet the relevant British Standard in force at the time of installation. The standards currently in force for new systems are BS EN 12566-3 for small wastewater (sewage) treatment plants.

    Your small package wastewater (sewage) treatment plant meets the British Standard in place at the time of installation if: it has a CE mark; the manual or other documentation that came with your tank or treatment plant has a certificate of compliance with a British Standard; it’s on British Water’s list of approved equipment. You can also ask the company that installed your equipment to confirm that it complies with the British Standard that was in place at the time the equipment was installed.

    Diamond - All of the plants within our domestic package sewage treatment range will be eligible to apply for an exemption as long as they do not exceed 5m3 per day to water course or 2m3 per day to a drainage filed. The EA will inform applicants if they are not eligible for a registration and therefore require a permit.


    If you have a small package wastewater (sewage) treatment plant on your property in Scotland, it must additionally be registered with the Scottish Environment Protection Agency (SEPA). This must be presented when a new property is being built or an existing property changes hands. For further information, please contact the Scottish Protection Agency.


    If you have a small package wastewater (sewage) treatment plant on your property in Wales, it must additionally be registered with Natural Resources Wales. For further information, please contact Natural Resources Wales.


    For further information, please contact Ireland Environment Protection Agency.

  • How far from a building should a domestic wastewater (sewage) treatment plant be sited?
    England - Environment Agency Building Regulations (Part H-H2 Package Sewage Treatment Works) state that all sewage treatment plants should be sited 7m-10m from any inhabited part of the property.  The building control officer for the site will make the final decision on exactly how far the plant should be sited. If the discharge is to a drainage field a sampling chamber must be provided before the drainage field. Drainage field drains must be constructed in the aerobic soil layer, i.e. within 700mm of ground level. Please visit your local Planning Portal website for further information. Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.



  • What is domestic wastewater?
    Domestic wastewater tends to originate from plumbing fixtures and appliances. This can include waste from toilets, dish washing, laundry, bath, shower, water  softeners or other sources that cause an increased load or inhibit bacterial growth.



  • What is the difference between a septic tank and a package wastewater (sewage) treatment plant?

    Unlike the traditional septic tanks, the modern package wastewater (sewage) treatment plants are designed with an aerated process for todays’ increased volume of water usage in everyday life. 

    Septic tank: Typically, a septic tank is found underground, receiving untreated wastewater (sewage) from a property and allowing the heavier solids to settle at the bottom whilst the effluent rises to the top. Naturally occurring bacteria helps the system break down the solids and sludge, with the remaining liquids flowing out of the tank into a drainage field. Septic tanks only provide partial treatment: settlement and separation of the solid waste and will normally discharge to a sub-surface soakaway or ditch.

    Small package wastewater treatment plant: On the other hand, a small package wastewater (sewage) treatment plant provides significant biological breakdown of the organic and chemical contaminants by using air to circulate and treat the contaminants to a much higher standard than a septic tank. Package wastewater (sewage) treatment systems “clean” the wastewater significantly, which permits effluent discharge into less porous soils,effluent can then be discharged into a water course, drainage ditches and a drainage field. Please check your local environment agency (England, Scotland, Wales and Northern Ireland) for regulations.

    Diamond: The small package wastewater (sewage) treatment plant has an added advantage of a high quality process in a compact, single tank which is easy to install and maintain. The successfully treated liquid that is discharged from the Diamond wastewater treatment plant is of a higher quality standard than a septic tank. This means that our wastewater treatment plant will help to prevent your drainage field from blocking. If discharging in to a running water course, our sewage treatment plant can help to reduce your environmental impact.