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
1st April 2025
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
1st April 2025
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
Name
CSD 0301 - Data Catalogue
Version
Effective from date
6th December 2024
8th November 2024
10th May 2024
12th May 2023
29th November 2022
13th May 2022
14th May 2021
6th November 2020
9th September 2020
14th February 2020
11th November 2019
26th July 2019
17th May 2019
29th March 2019
26th October 2018
28th September 2018
25th May 2018
18th May 2018
30th March 2018
1st April 2017
Name
CSD 0301 - Error Codes
Version
Effective from date
10th May 2025
13th May 2024
12th May 2023
27th November 2023
2nd December 2022
23rd May 2022
4th December 2021
14th May 2021
6th November 2020
15th May 2020
28th August 2020
24th September 2019
25th October 2019
4th November 2019
8th November 2019
17th May 2019
26th June 2019
19th September 2018
19th October 2018
11th April 2018
20th April 2018
17th May 2018
21st June 2018
23rd March 2017
20th September 2017
23rd March 2017
10th May 2017
Name
CSD 0302 - Standing Reports and Data Extracts
Version
Effective from date
1st April 2025
26th June 2024
13th March 2024
12th December 2023
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
31st May 2022
13th May 2022
22nd September 2021
15th February 2021
6th November 2020
9th September 2020
26th July 2019
17th May 2019
26th October 2018
28th March 2018
1st April 2017
Name
CSD 0400 - Common interface technical specifications
Version
Effective from date
26th June 2024
22nd September 2021
3rd December 2018
1st April 2017
Name
CSD 0401 - Transactional interface for Trading Parties having a high volume of Data Transactions
Version
Effective from date
29th November 2022
22nd September 2021
17th May 2019
3rd December 2018
1st April 2017
Name
CSD 0402 - Transactional interface for Trading Parties having a low volume of Data Transactions
Version
Effective from date
29th November 2022
22nd September 2021
1st April 2017
Name
CSD 0403 - Interface for the provision of Reports from the Market Operator to Trading Parties
Version
Effective from date
17th May 2019
3rd December 2018
1st April 2017
Name
CSD 0404 - Interface for the provision of non-transactional Data Items from Trading Parties
Version
Effective from date
1st April 2017
Name
CSD 0405 - Data Query Interface
Version
Effective from date
1st April 2017
Name
CSD 0406 - Service Management Interface
Version
Effective from date
3rd December 2018
1st April 2017
Name
CSD 0501 - Change Management Implementation
Version
Effective from date
14th January 2022
14th May 2021
1st April 2017
Name
CSD 0601 - Bilateral Data Catalogue
Version
Effective from date
13th December 2024
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
Name
Form H/01: request for an allowance to wholesale charges for a change to an existing allowance
Version
Effective from date
30th March 2018
1st April 2017
Name
Form H/02: request for a contribution offer for a meter to be installed at an unmeasured supply point
Version
Effective from date
30th March 2018
1st April 2017
Name
Form H/05: Application for Gap Site Incentive
Version
Effective from date
30th March 2018
1st April 2017
Name
Form H/06: Application for Vacancy Incentive Scheme Payment
Version
Effective from date
15th May 2020
30th March 2018
1st April 2017
Name
OSD 0701 - Bilateral Common Processes
Version
Effective from date
1st April 2025
13th December 2024
2nd October 2024
26th June 2024
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
2nd February 2022
22nd September 2021
Name
OSD 0702 - Bilateral Processes for Part A
Version
Effective from date
1st April 2025
26th June 2024
13th March 2024
Name
OSD 0703 - Bilateral Processes for Part B
Version
Effective from date
1st April 2025
26th June 2024
13th March 2024
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
31st May 2022
Name
OSD 0704 - Bilateral Processes for Part C
Version
Effective from date
1st April 2025
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
2nd February 2022
22nd September 2021
Name
OSD 0705 - Bilateral Processes for Part D
Version
Effective from date
1st April 2025
2nd October 2024
26th June 2024
Name
OSD 0706 - Bilateral Processes for Part E
Version
Effective from date
1st April 2025
2nd October 2024
26th June 2024
Name
OSD 0707 - Bilateral Processes for Part F
Version
Effective from date
1st April 2025
2nd October 2024
26th June 2024
13th March 2024
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
31st May 2022
Name
OSD 0708 - Bilateral Processes for Part G
Version
Effective from date
1st April 2025
13th March 2024
27th September 2023
20th June 2023
29th November 2022
2nd August 2022
31st May 2022
Name
OSD 0709 - Bilateral Processes for Part H
Version
Effective from date
1st April 2025
13th March 2024
12th December 2023
27th September 2023
20th June 2023
Name
OSD 0710 - Bilateral Processes for Part I
Version
Effective from date
1st April 2025
26th June 2024
13th March 2024
12th December 2023
Name
OSD 0711 - Bilateral Processes for Part J
Version
Effective from date
1st April 2025
2nd October 2024
26th June 2024
Code Defined Documents
Name
Allowance and or Volumetric Adjustment
Version
Effective from date
20th June 2023
Name
New Supply Point Customer Application Form
Version
Effective from date
13th March 2024
Name
Trade Effluent
Version
Effective from date
29th November 2022
Name
Gap Site Incentive Scheme - Guidance
Version
Effective from date
8th November 2024
5th April 2024
28th March 2024
15th January 2024
20th June 2023
29th November 2022
12th April 2022
1st April 2022
6th January 2021
5th October 2020
24th September 2020
10th September 2020
2nd September 2020
14th August 2020
1st April 2020
Name
Gap Site Incentive Scheme - Schedule of Rates
Version
Effective from date
8th November 2024
Name
Vacancy Incentive Scheme - Guidance
Version
Effective from date
8th November 2024
15th January 2024
27th April 2021
14th August 2020
15th May 2020
Name
Vacancy Incentive Scheme - Schedule of Rates
Version
Effective from date
8th November 2024
Name
Accredited Entity Disconnection Application Form
Version
Effective from date
26th June 2024
Name
Accredited Entity Metering Application Form
Version
Effective from date
26th June 2024
Name
Accredited Entity Reconnection Application Form
Version
Effective from date
26th June 2024
Name
Gap Site Letter Template
Version
Effective from date
29th November 2021
Name
Non-Market Meter Read Application Form
Version
Effective from date
13th March 2024
Name
Private and Cross Border Meter Activity Application Form
Version
Effective from date
13th March 2024
Name
Wholesaler Action Notification Template
Version
Effective from date
2nd October 2024
26th June 2024
13th March 2024
Name
Wholesaler Unplanned Events Template
Version
Effective from date
26th June 2024
Withdrawn
Name
Form A/01: Pre-application enquiry in relation to a new connection - Withdrawn
Version
Effective from date
26th July 2019
30th March 2018
23rd March 2017
Name
Form A/02: Application to connect to the wholesaler's water supply system - Withdrawn
Version
Effective from date
26th July 2019
30th March 2018
1st April 2017
Name
Form A/03: Application for a building water supply - Withdrawn
Version
Effective from date
26th July 2019
30th March 2018
1st April 2017
Name
Form A/04: Application to connect to the wholesaler's sewerage system - Withdrawn
Version
Effective from date
26th July 2019
30th March 2018
1st April 2017
Name
Form A/05: application to be registered as a retailer to a newly connected supply point for water and/or sewerage - Withdrawn
Version
Effective from date
13th March 2024
30th March 2018
1st April 2017
Name
Form B/01: metering activity carried out by the wholesaler - Withdrawn
Version
Effective from date
13th March 2024
29th November 2022
2nd August 2022
31st May 2022
30th March 2018
1st April 2017
Name
Form B/02: metering activity carried out by an accredited entity - Withdrawn
Version
Effective from date
26th June 2024
30th March 2018
1st April 2017
Name
Form B/03: request for Non-Market Meter Read to be carried out by the wholesaler - Withdrawn
Version
Effective from date
13th March 2024
30th March 2018
1st April 2017
Name
Form C/01: Verification of meter details or meter supply arrangements - Withdrawn
Version
Effective from date
22nd September 2021
30th March 2018
1st April 2017
Name
Form C/02: addition of service components - Withdrawn
Version
Effective from date
27th September 2023
29th November 2022
30th March 2018
1st April 2017
Name
Form C/03: request for de-registration of a supply point or removal of service components - Withdrawn
Version
Effective from date
29th November 2022
30th March 2018
1st April 2017
Name
Form C/04: request for wholesaler to amend third-party references - Withdrawn
Version
Effective from date
27th September 2023
30th March 2018
1st April 2017
Name
Form F/01: enquiries and record of drinking water enquiries - Withdrawn
Version
Effective from date
31st May 2022
28th September 2018
30th March 2018
1st April 2017
Name
Form F/02: complaints and record of drinking water complaints and concerns - Withdrawn
Version
Effective from date
31st May 2022
30th March 2018
1st December 2017
1st April 2017
Name
Form G/01: trade effluent enquiries - Withdrawn
Version
Effective from date
31st May 2022
30th March 2018
1st April 2017
Name
Form G/02: trade effluent discharge application - Withdrawn
Version
Effective from date
29th November 2022
28th September 2018
30th March 2018
1st April 2017
Name
Form G/03: Temporary trade effluent discharge application - Withdrawn
Version
Effective from date
29th November 2022
1st April 2017
Name
Form H/03: request for a review of assessed or unmeasured charges - Withdrawn
Version
Effective from date
12th December 2023
30th March 2018
1st April 2017
Name
Form H/04: application for change in tariff - Withdrawn
Version
Effective from date
12th December 2023
28th September 2018
30th March 2018
1st April 2017
Name
Form I/01: retailer disconnection request - Withdrawn
Version
Effective from date
26th June 2024
12th December 2023
30th March 2018
1st April 2017
Name
Form I/02: non-household customer disconnection request - Withdrawn
Version
Effective from date
26th June 2024
12th December 2023
30th March 2018
1st April 2017
Name
Form I/03: request for wholesaler to use wholesaler's powers of entry for the purposes of disconnection - Withdrawn
Version
Effective from date
12th December 2023
30th March 2018
1st April 2017
Name
Form I/04: request for reconnection of a supply which has been temporarily disconnected - Withdrawn
Version
Effective from date
26th June 2024
12th December 2023
26th July 2019
30th March 2018
1st April 2017
Name
Form I/05: Disconnection performed by the Wholesaler in relation to non-payment in cases of a Self-Supply Retailer - Withdrawn
Version
Effective from date
12th December 2023
30th March 2018
1st April 2017
Name
Annex A - process diagrams - Withdrawn
Version
Effective from date
26th June 2024
13th March 2024
26th July 2019
1st April 2017
Name
Annex B - process diagrams - Withdrawn
Version
Effective from date
26th June 2024
13th March 2024
29th November 2022
2nd August 2022
31st May 2022
1st April 2017
Name
Annex C - process diagrams - Withdrawn
Version
Effective from date
26th June 2024
27th September 2023
29th November 2022
22nd September 2021
13th November 2020
1st April 2017
Name
Annex D - process diagrams - Withdrawn
Version
Effective from date
26th June 2024
14th May 2021
1st April 2017
Name
Annex E - process diagrams - Withdrawn
Version
Effective from date
26th June 2024
1st April 2017
Name
Annex F - process diagrams - Withdrawn
Version
Effective from date
13th March 2024
31st May 2022
1st April 2017
Name
Annex G - process diagrams - Withdrawn
Version
Effective from date
13th March 2024
29th November 2022
31st May 2022
28th August 2020
28th September 2018
1st April 2017
Name
Annex I - process diagrams - Withdrawn
Version
Effective from date
26th June 2024
12th December 2023
3rd July 2017
1st April 2017
Related pages
Change
The status of changes, information on current and past changes and how to raise a change.
Learn moreThe Code Change Committee
Find out more about the Code Change Committee, who are responsible for recommending changes to the non-household water market rules.
Learn more