Market Codes
This page contains the latest versions of the market codes, alongside guidance documents on industry processes, changes to the codes and consultations.
Governing the Market
The codes that govern the non-household retail market are the Market Arrangements Code (MAC) and the Wholesale Retail Code (WRC). The MAC is a non-statutory code established by licence conditions set out by Ofwat. The WRC is a statutory code forming the agreement entered into by wholesalers with those retailers they are providing services to.
The codes and any changes to them are approved by Ofwat and maintained by MOSL. If you have any queries on the market codes, please contact codechange@mosl.co.uk.
Key documentation
The Market Codes Structural Outline sets out the structure of the Market Codes framework, made up of the Market Codes and their associated documents. This document is owned by the Strategic Panel and is reviewed by the Strategic Panel as required.
The Baseline Statement lists the current versions of all market codes framework documents along with training, guidance, and policy documents. It includes their current version, updates, change process and ownership. The Baseline Statement is owned by MOSL and updated with each release of the Market Codes or supporting documents.
Market Codes
Name
1.0 Market Arrangements Code
Version
Effective from date
6th December 2024
21st November 2024
26th June 2024
4th April 2024
16th February 2024
18th December 2023
22nd May 2023
3rd March 2023
1st March 2022
14th January 2022
17th November 2021
5th November 2021
22nd September 2021
1st September 2021
14th May 2021
1st February 2021
28th January 2021
13th November 2020
6th November 2020
7th October 2020
9th September 2020
1st September 2020
28th August 2020
1st August 2020
1st July 2020
1st June 2020
8th April 2020
1st April 2020
23rd March 2020
1st January 2020
20th September 2019
23rd August 2019
26th July 2019
1st April 2019
29th March 2019
31st July 2018
30th March 2018
16th March 2018
1st December 2017
15th September 2017
17th July 2017
1st April 2017
Name
2.0 Schedule 1 Terms and Conditions of a Wholesale Contract
Version
Effective from date
22nd September 2021
1st April 2017
Name
2.1 Schedule 1 Part 1 Objectives, Principles and Definitions
Version
Effective from date
21st November 2024
8th November 2024
13th March 2024
18th December 2023
27th October 2023
20th June 2023
29th November 2022
2nd August 2022
1st March 2022
5th November 2021
22nd September 2021
1st September 2021
26th January 2021
13th November 2020
6th November 2020
23rd October 2020
9th September 2020
28th August 2020
1st August 2020
15th May 2020
1st May 2020
1st April 2020
1st April 2020
7th November 2019
30th September 2019
26th July 2019
29th March 2019
31st January 2019
31st July 2018
3rd July 2017
1st April 2017
Name
2.2 Schedule 1 Part 2 Business Terms
Version
Effective from date
21st November 2024
8th November 2024
16th February 2024
7th April 2023
26th August 2022
2nd August 2022
5th November 2021
22nd September 2021
1st September 2021
14th May 2021
13th November 2020
6th November 2020
23rd October 2020
5th August 2020
1st August 2020
1st May 2020
16th April 2020
1st April 2020
30th March 2020
14th February 2020
30th September 2019
29th March 2019
28th February 2019
31st January 2019
31st July 2018
23rd April 2018
30th March 2018
14th July 2017
1st April 2017
Name
2.3 Schedule 1 Part 3 Operational Terms
Version
Effective from date
2nd October 2024
26th June 2024
13th March 2024
12th December 2023
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
31st May 2022
2nd February 2022
22nd September 2021
1st September 2021
14th May 2021
9th September 2020
28th August 2020
15th May 2020
8th April 2020
1st April 2020
26th July 2019
1st April 2019
28th September 2018
3rd March 2018
1st December 2017
3rd July 2017
1st April 2017
Name
2.4 Schedule 1 Part 4 Market Terms
Version
Effective from date
21st November 2024
8th November 2024
18th December 2023
29th November 2022
26th August 2022
1st March 2022
22nd September 2021
14th May 2021
26th January 2021
13th November 2020
6th November 2020
9th September 2020
1st April 2020
14th February 2020
28th February 2019
3rd December 2018
28th September 2018
31st August 2018
18th May 2018
1st April 2017
Name
Annex H - process diagrams
Version
Effective from date
12th December 2023
20th June 2023
13th November 2020
1st April 2017
Name
CSD 0001 - Market Entry Assurance and Market Re-assurance
Version
Effective from date
21st November 2024
8th November 2024
29th November 2022
5th November 2021
22nd September 2021
12th March 2018
1st April 2017
Name
CSD 0002 - Market Performance Framework
Version
Effective from date
21st November 2024
8th November 2024
13th March 2024
18th January 2024
18th December 2023
12th December 2023
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
31st May 2022
2nd February 2022
22nd September 2021
14th May 2021
15th February 2021
9th September 2020
1st August 2020
1st July 2020
1st June 2020
1st April 2020
23rd March 2020
1st November 2019
26th July 2019
1st April 2019
18th May 2018
29th March 2018
3rd March 2018
1st April 2017
Name
CSD 0003 - Volume Transfer and Volume Data Update
Version
Effective from date
8th November 2024
2nd February 2022
22nd September 2021
1st April 2017
Name
CSD 0004 - Interim Supply Process
Version
Effective from date
27th October 2023
2nd February 2022
22nd September 2021
9th September 2020
1st April 2017
Name
CSD 0005 - Direction to Supply Allocation Process
Version
Effective from date
1st April 2017
Name
CSD 0006 - Trading Party Administration and Notification Processes
Version
Effective from date
8th November 2024
20th June 2023
22nd September 2021
9th September 2020
3rd December 2018
26th October 2017
1st April 2017
Name
CSD 0007 - Business Continuity Management
Version
Effective from date
22nd September 2021
28th August 2020
29th March 2019
3rd December 2018
1st April 2017
Name
CSD 0101 - Registration: New Supply Points
Version
Effective from date
20th June 2023
14th May 2021
15th May 2020
26th October 2018
18th May 2018
29th March 2018
2nd October 2017
1st April 2017
Name
CSD 0102 - Registration: Transfers
Version
Effective from date
2nd February 2022
22nd September 2021
14th May 2021
15th February 2021
9th September 2020
7th November 2019
29th March 2019
26th October 2018
1st April 2017
Name
CSD 0103 - Registration: Cancellations and Erroneous Transfers
Version
Effective from date
20th June 2023
2nd February 2022
22nd September 2021
1st April 2017
Name
CSD 0104 - Maintain SPID Data
Version
Effective from date
10th May 2024
29th November 2022
23rd October 2020
1st August 2020
30th March 2020
26th July 2019
17th May 2019
26th October 2018
2nd October 2017
1st April 2017
Name
CSD 0105 - Error Rectification and Retrospective Amendments
Version
Effective from date
14th May 2021
19th July 2022
7th November 2019
17th May 2019
29th March 2019
28th September 2018
2nd October 2017
1st April 2017
Name
CSD 0106 - Non-Market Meters
Version
Effective from date
10th May 2024
1st April 2017
Name
CSD 0201 - Settlement Timetable and Reporting
Version
Effective from date
14th February 2020
31st August 2018
1st December 2017
1st April 2017
Name
CSD 0202 - Meter Read Submission: Process
Version
Effective from date
25th August 2023
20th June 2023
12th May 2023
13th May 2022
9th July 2021
14th May 2021
15th February 2021
6th November 2020
9th September 2020
29th March 2019
1st April 2017
Name
CSD 0203 - Meter Read Submission: Validation
Version
Effective from date
8th November 2024
12th May 2023
14th May 2021
15th February 2021
28th September 2018
1st April 2017
Name
CSD 0206 - Trade Effluent Processes
Version
Effective from date
13th March 2024
29th November 2022
6th November 2020
26th July 2019
28th September 2018
1st April 2017
Name
CSD 0207 - Charge Calculation, Allocation and Aggregation
Version
Effective from date
29th November 2022
15th February 2021
14th February 2020
29th March 2019
1st April 2017
Name
CSD 0208 - Creation and update of Wholesaler Tariff Data
Version
Effective from date
17th May 2019
1st April 2017