Information letters and advice notes

The Drinking Water Inspectorate uses Information letters and Advice notes to communicate with the water industry, local authorities and other relevant parties.

Information letters are used by DWI to communicate any changes in regulatory matters and Advice notes relate to changes in guidance or procedures.

They are automatically sent to named contacts but are available on request to anyone.

The list below includes only those letters that contain current information. Many older letters have been superseded. However, copies of such letters are available by contacting dwi.enquiries@defra.gov.uk

2021

REF

TITLE

Annex

05/2021 (Oct 21)

INFORMATION LETTER

Requirements for Poly and Perfluorinated Alkyl Substances (PFAS) monitoring by water companies in England and Wales (PDF 121KB)

N/A

04/2021 (Sep 21)

INFORMATION LETTER

Code of Practice on Technical Aspects of Fluoridation of Water Supplies 2021 (PDF 113KB)

Code of Practice on Technical Aspects of Fluoridation of Water Supplies 2021 (PDF 561KB)

03/2021 (Aug 21)

INFORMATION LETTER

Radioactivity Notices (exemptions for monitoring) under the Water Supply (Water
Quality) Regulations 2016 (as amended) (England) and the Water Supply (Water
Quality) Regulation 2018 (Wales) (PDF 118KB) 

 Annex A – Conditions and Requirements for Radioactivity Exemption Applications (PDF 111KB)

02/2021 (Apr 21)

INFORMATION LETTER

The Water Industry (Suppliers’ Information) Direction 2021 (PDF 113KB) 

Information Direction 2021 (PDF 260KB) – supersedes the Water Industry (Suppliers’ Information) Direction 2020

01/2021 (Apr 21)

INFORMATION LETTER

Reporting of Treatment Chemicals, Service Reservoir, Contact Tank and Final Water Storage Tank Information (PDF 53KB)

Annex A – Guidance and Specification (PDF 167KB)

Service reservoirs, contact tanks and final water tanks template (XLS 19KB)

Treatment chemicals template (XLS 19KB)

2020

REF

TITLE

Annex

07/2020 (Nov 20)

INFORMATION LETTER

The Water Industry (Suppliers’ Information) Direction 2020 (PDF 80KB)

Information Direction (PDF 104KB)

06/2020 (Sept 20)

INFORMATION LETTER

Assessment of the limitations for chemicals and treatment products intended for the treatment of drinking water (PDF 93KB)

N/A

05/2020 (July 20)

INFORMATION LETTER

Chloramination disinfection and associated risks of cyanide formation in treated water (PDF 106KB)

N/A

04/2020
(May 20)

INFORMATION LETTER

Information Letter 04/2020 is revoked

N/A

02/2020
(May 20)

ADVICE NOTE

Maintaining drinking water quality when reinstating water supplies after temporary closure due to the CoViD-19 outbreak (PDF 97KB)

Welsh version: At Aelodau Bwrdd a Chysylltiadau Bob Dydd Cwmnïau Dŵr a Charthffosiaeth a Chwmnïau Dŵr yng Nghymru a Lloegr (PDF 190KB)

N/A

01/2020
(Apr 20)

ADVICE NOTE

Water suppliers’ responsibilities under Section 75(2) of the Water Industry Act 1991, the Water Supply (Water Fittings) Regulations 1999 and the Water Supply (Water Quality) Regulations 2016 (as amended) or the Water Supply (Water Quality) Regulations 2018 (Wales) (PDF 162KB)

N/A

03/2020
(Apr 20)

INFORMATION LETTER

Information Letter 03/2020 is revoked

N/A

02/2020
(Mar 20)

INFORMATION LETTER

Information Letter 02/2020 is revoked

N/A

01/2020
(Mar 20)

INFORMATION LETTER

Information Letter 01/2020 is revoked

N/A

2019

REF

TITLE

Annex

04/2019 (Aug 19)

INFORMATION LETTER

Drinking Water Inspectorate Risk Management Approval Scheme (DWIRMAS) (PDF 114KB)

DWIRMAS Guidance (PDF 606KB)

03/2019 (Jun 19)

INFORMATION LETTER

The Water Industry (Suppliers’ Information) Direction 2019 (PDF 248KB)

The Information Direction 2019 (PDF 92KB)

Annex A (PDF 54KB) Updated GIS Specification

Annex B (PDF 133KB) Revised file specification for compliance data returns

Annex C (Excel 166KB) Updated Parameter list (updated Sept 2021)

02/2019 (Apr 19)

INFORMATION LETTER

Reporting Requirements under Regulation 28 of the Water Supply (Water Quality) Regulations 2016 (as Amended) and the Water Supply (Water Quality) Regulations 2018 (Wales) (the Regulations) (PDF 74KB)

Annex A Guidance and Specification – Regulation 28 Reports (PDF 203KB)

01/2019 (Apr 19)

INFORMATION LETTER

Drinking Water Quality Legislation (PDF 127KB)

N/A

2018

REF

TITLE

Annex

03/2018 (Dec 18)

INFORMATION LETTER

METALDEHYDE – Recent developments and actions required (PDF 127KB)

N/A

02/2018 (Aug 18)

INFORMATION LETTER

Monitoring Variations under Regulation 9 and Reporting Requirements under Regulation 28 of the Water Supply (Water Quality) Regulations 2016 (as Amended) and the Water Supply (Water Quality) Regulations 2018 (Wales) (the Regulations(PDF 143KB)

Annex A – Guidance and Data Specification – Monitoring Variation Applications (PDF 173KB) (Version 2 updated Nov19)

Annex B –  Guidance and Specification – Regulation 28 Reports Updated in annex A of IL 02/2019 (PDF 203KB)

01/2018 (Jul 18)

INFORMATION LETTER

Drinking Water Quality Legislation (PDF 87KB)

N/A

2017

REF

TITLE

Annex

04/2017 (Dec 17)

INFORMATION LETTER

Regulatory Sampling Programme (PDF 63KB)

N/A

03/2017 (Sept 17)

INFORMATION LETTER

Update to guidance documents including a guidance note on long term planning for drinking water quality (PDF 119KB)

N/A

02/2017
(May 17)

INFORMATION LETTER

Further guidance on Chromium in drinking water (PDF 122KB)

N/A

2016

REF

TITLE

Annex

04/2016
(Jun 16)

New drinking water quality legislation (2016) (PDF 152KB)

N/A

02/2016
(Mar 16)

Legislative changes relating to the DWI cost recovery scheme (PDF 61KB)

N/A

2015

2014

REF

TITLE

Annex

02/2014

Regulation 28 reporting requirements (PDF 110KB)

A – General requirements
Updated in annex A of IL 02/2019 (PDF 203KB)
B – Specification
Updated in annex B of IL 02/2019 (PDF 203KB)
C – Parameter/Hazard list (XLS 166KB)
Updated September 2021

D – Example tables (Zip file 173KB)
Updated September 2014
E – Query log (XLS 125KB)
Updated 12 November 2014

01/2014

Metaldehyde and other pesticides (PDF 134KB)

N/A

2013

REF

TITLE

Annex

05/2013

Drinking water analysis and the regulatory requirements (PDF 95KB)

N/A

04/2013

Collection of data under the Private Water Supplies Regulations 2009 and the Private Water Supplies (Wales) Regulations 2010 (PDF 107KB)

1 – Return template (excel 438KB)
Updated Oct 2020
Guidance on additional columns(pdf360KB) relating to radioactivity monitoring Updated Nov 2017
2 – Example return (excel 466KB)
Updated October 2018
3 – Specification (PDF 202KB)
Updated Oct 2020
FAQ (PDF 252KB)

2012

2011

2010

2009

2007

2006

REF

TITLE

Annex

01/2006 

Annual Provision of Information on Consumer Contacts (PDF 172KB)

Example return (PDF 67KB)

2005

2004

2003

REF

TITLE

Annex

12/2003

Procedures for the Delivery of Water Treatment Chemicals (PDF 82KB)

N/A

2001

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