The market operator for the water retail market in England.

Our story

MOSL was established in 2015 as a not-for-profit company to operate, develop and design the new business water market, which opened on 1 April 2017.

We played a key role in the preparations to launch and open the market, by designing, building and implementing the central IT systems – known as CMOS – which sits at the heart of the new market.

We actively supported the development and evolution of the market codes and arrangements which govern the market, through the Market Arrangements Code (MAC) Panel. And we provided important assistance to both wholesaler and retailer water companies’ preparations, to make sure the market opened on time, on budget and in good shape on 1 April 2017. Find out more about who we are, what we do and how we do it below.



Who we are

MOSL is responsible for the smooth and efficient running of a new and growing business water market. The new market opened in April 2017 and allows 1.2 million businesses including public sector bodies, charities and not-for-profit organisations in England to choose who supplies their retail water services.

We make it possible for new companies to enter the market, ensuring that they can do business easily and at a low cost. When customers choose to change suppliers, we enable the transactions in our central IT system (CMOS), ensuring that smooth settlement and payments take place between the wholesalers and retailers.

The direction of our business is underpinned by our vision, purpose and business objectives, which are described in our Strategy. There are two guiding principles that dictate our direction for the foreseeable future. First is the need for cost efficiency, and the second is pursuing this while also prioritising the stabilisation of the market.

What we do

Our aim, at all times, is to run an efficient and resilient market with the trust and collaboration of our members. It’s vital that we use our skills and expertise to keep the new market evolving and improving.

We aspire to be collaborative in our approach to market improvement, and to champion innovative ways of reducing market friction, while ensuring a level playing field. This means reducing any barriers for companies entering the market and ensuring that all players have the same opportunities for operating and engaging with us and the industry.

Our experts design and deploy the infrastructure, information and governance services that make it possible for customers to move smoothly from one supplier to another using our central IT system, which supports over 3,600 users, processing 85,000 transactions every day.

The market operates through a series of rules and arrangements known as Codes. These are another key part of MOSL’s responsibilities. We provide the secretariat for the Market Arrangements Code (MAC) Panel and its five committees, which oversee and review these rules, with input from our members.


Our values


We are a learning organisation, using our knowledge, experience and analytical skill to get inside complex issues. We make sound, evidence-based decisions in a fair and impartial way and look for new and innovative ways to solve problems.


We welcome diversity of opinion as a source of strength and are consultative in our approach. We understand the needs and views of others, recognising they may legitimately see things differently to us.                                                      


We are open, honest and accountable, communicating clearly and succinctly. We are clear about our intentions and the reasons behind our decisions. We cut through complexity to make things intuitive, clear and simple.


We use our knowledge to help shape both the market and the views of stakeholders in the best interest of the market. We take decisions, engage with issues and track progress.                                                                           


Our Strategy

Our Strategy has been developed to drive forward the company and ensure that we play our part in the effective and efficient operation of the business retail water market.

It outlines our vision and purpose and sets out our responsibility to the market and its customers through the services we provide.

Our vision

A competitive market that benefits end customers

Our purpose

To provide the infrastructure, information and governance services effectively and efficiently to enable the competitive retail water market to operate and evolve for the benefit of end customers

You can read the full Strategy document here.

Moving to a new home

In February 2018, we decided to relocate our headquarters out of London. This was part of a wider strategic review about what was in the best interests of both the market and MOSL. With the market now open, this was the right time for the company to look forward to its long-term future and how we could best deliver on the promises we set out in our Strategy and through the Business Plan 2019/2020.

Southampton is one of the most vibrant and fastest-growing economies in the UK. It is attracting more businesses and start-ups than ever before. The ‘Master Plan’, launched by Southampton City Council in 2012, is projected to bring 24,000 jobs to the city by 2030 through a new business quarter and a £175 million redevelopment of the cultural quarter and waterfront area.

We want to attract and invest in high-quality, highly-skilled people and allow them to fulfil their potential. Moving to Southampton marks an exciting step in our journey. We are committed to investing in the future of our company and our people, for the benefit of the market and our customers. To find out more about working for MOSL and to take a look at our current vacancies, visit our dedicated Careers Page.


The White Building

Brand new offices

Collaborative breakout areas

Dedicated conference facilities

Contemporary design and layout

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