DMS (1 – 20 occupancy equivalent)

Discover the WPL Diamond DMS

Discreet wastewater treatment


Small tank, big results!

If your property is not connected to mains sewerage, your wastewater can be treated by our discreet below ground WPL Diamond DMS package wastewater treatment range.

This is a small and compact wastewater treatment plant designed for properties that house 1 person or up to 20 (people) occupancy equivalent; ideal for new builds and replacement of existing septic tank systems and package sewage treatment plants.

Using no chemicals, our system treats to a very high standard, so that the final effluent can be safely discharged to a soakaway, watercourse or drainage ditch.

Our WPL Diamond is better designed for modern day living than a septic tank system; with a faster process and a more environmentally friendly end result, it is the ideal replacement solution.

Typical domestic uses

Single houses

Rural barn conversions

Replacement of septic tank systems

Typical commercial uses

Bed and breakfasts

Small commercial buildings and offices

Small retail such as farm shops

Replacement of septic tank systems

Key features

25 years warranty*

Comes with 25 years tank warranty and a process performance guarantee for the life of the tank. The air blower (housed in the kiosk) warranty is 2 years.

Longer emptying cycle*

Sludge (the product of our refining process) growth rate within the tank is reduced due to our unique aeration process, which breaks down organic matter and results in longer emptying cycles of up to three years.

No odours*

The WPL Diamond wastewater treatment range is odourless so you won’t even know it’s there!


No hidden costs

The standard package includes a WPL Diamond DMS tank, WPL kiosk, alarm beacon, blowers and 10 metres air hose. Additional extras are available.

Simple installation

Our robust WPL Diamond plant is compact in design, keeping the excavation to a minimum and the installation simple, with little disruption.

Low user maintenance

Economical to run long term and unlike other wastewater (sewage) treatment plants on the market, the unique design of the WPL Diamond DMS has no internal electrical or mechanical moving parts, requiring minimal annual maintenance.

*subject to correct installation, consistent influent conditions and regular plant maintenance as per the manufacturers’ instructions.

Easy on the eye and the landscape

Our WPL Diamond DMS is entirely underground, boasting the flushest lid on the market and ensuring minimal visual impact to your beautiful garden or surrounding landscape.

Fully compliant

The high quality WPL 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.

Kind to the environment

Unlike other tanks on the market, our WPL Diamond has no need for additional chemicals, to reduce our environmental impact.

Environment Agency approved

The liquid matter (effluent) discharged by our WPL Diamond range is fully compliant with the regulations set by Environment Agency (EA) and exceeds normal consent standards.

WPL Diamond Process

Our WPL Diamond has the advantage of a high quality process for wastewater treatment; in a compact single tank which is easy to install and maintain.



Ideal septic tank replacement

The successfully treated liquid that is discharged from the WPL Diamond package 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 soakaway from blocking. If discharging in to a running water course, our WPL Diamond can help to reduce your environmental impact.    

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

From 1st January 2020 (or before if you are selling your property in England), a septic tank must be upgraded if it is currently discharging to a watercourse. This is due to a pollution risk to the environment because of the poor quality of wastewater that it emits.

The WPL Diamond has more discharge options and an added advantage of a high quality process in
a compact, single tank which is easy to install and maintain.

Looking for technical information?

Technical zone

WPL Diamond standards

BS EN 12566-3

CE marked, fully type tested and certificated in accordance with the mandatory European standard BS EN12566-3 2014 for small wastewater treatment systems.

LABC approved

LABC approved England and Wales, which means the WPL Diamond has been assessed against Building Regulation requirements and can be installed without the need to have it signed off again by building control.

Part H2 for building regulations

The WPL Diamond is fully compliant in the UK with HM government guidance for Drainage and Waste Disposal, Part H2 for building regulations of wastewater treatment systems.

General binding rules

Meets current legislation for exemption from a permit to discharge by the Environment Agency (EA), England, as per the General Binding Rules document.

British Water Flows and Loads code of practice

Designed using the British Water Flows and Loads code of practice, to ensure correct sized tanks.

UK & European patented

The WPL Diamond is UK and European patented. This means that our design is completely unique. Patent number: GB 250337.

Accredited ISO 9001

ISO 9001 – Recognised for our Quality Management System requirements for all areas of the business.

Accredited OHSAS 18001

OHSAS 18001 – Our mission is to ensure that we enforce standards with our Occupational Health & Safety Management System.

Accredited ISO 14001

ISO 14001 – Recognised for our Environmental Management System compliance.

British Water Packaged Treatment Plant (PTP) Focus Group

WPL Technical Director, Andrew Baird is the convenor of British Waters’ PTP Focus Group, which has been formed to provide input to the continued development of British and European Standards. The group also promotes good practice in design, installation and maintenance of package wastewater (sewage) treatment plants up to 1000 population equivalent.

 Andrew is also a member of the British Standards Institute (BSI) committee on wastewater treatment plants. As a British Water’s representative in Working Group 41, he will help shape two British Standards (BS) that will also contribute to European Norms (EN).

WPL is also a member of British Water Trade Association for the UK Water and Wastewater Industry.


Investors in People

Investors in People is an internationally recognised accreditation for our standards of better people management.

Royal Institute of Architects (RIBA)

WPL present RIBA accredited CPD seminars on wastewater treatment to architects and civil engineers. RIBA champion better buildings, communities and the environment through architecture.

Composites UK

WPL is a member of Composites UK, an accredited trade association for the UK composites industry, promoting the best practice use of composites materials.

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