A lookup between 2011 Census enumeration postcodes for England and Wales, and the parishes / communities, wards and local authority districts as at 31 December 2011. Enumeration postcodes are a sub-Output Area (OA) geography used only for the publication of estimates of males, females and households in the 2011 Census. The enumeration postcodes are defined as only those valid unit postcodes that were recorded during the 2011 Census as containing usually resident population. Postcodes have been assigned using a ‘point-in-polygon’ methodology that plots each postcode's mean address (centroid) into the areas of each of the parishes / communities, wards and local authority districts (LAD). In England there is not a full coverage of parishes, so the 2011 Census enumeration postcodes that do not fall into a parish will have no parish allocation. There are also 23 parishes (0.2%) that do not contain any enumeration postcode centroids. This occurs where a parish contains population, but the centroid of the postcode falls outside the parish. In these instances it is not possible to allocate a postcode to the parish.

This is a lookup file between electoral wards/divisions and local authority districts in the United Kingdom as at 2nd May 2024. (File Size - 1.4 MB) Field Names - WD24CD, WD24NM, WD24NMW LAD24CD, LAD24NM, LAD24NMWField Types - Text, Text, Text, Text, Text, TextField Lengths - 9, 53, 45 9, 36, 24

This is the ONS Postcode Directory (ONSPD) for the United Kingdom as at February 2024 in Comma Separated Variable (CSV) and ASCII text (TXT) formats. This file contains the multi CSVs so that postcode areas can be opened in MS Excel. To download the zip file click the Download button. The ONSPD relates both current and terminated postcodes in the United Kingdom to a range of current statutory administrative, electoral, health and other area geographies. It also links postcodes to pre-2002 health areas, 1991 Census enumeration districts for England and Wales, 2001 Census Output Areas (OA) and Super Output Areas (SOA) for England and Wales, 2001 Census OAs and SOAs for Northern Ireland and 2001 Census OAs and Data Zones (DZ) for Scotland. It now contains 2021 Census OAs and SOAs for England, Wales and Northern Ireland. It helps support the production of area-based statistics from postcoded data. The ONSPD is produced by ONS Geography, who provide geographic support to the Office for National Statistics (ONS) and geographic services used by other organisations. The ONSPD is issued quarterly. (File size - 231 MB) Please note that this product contains Royal Mail, Gridlink, LPS (Northern Ireland), Ordnance Survey and ONS Intellectual Property Rights.

A best-fit lookup between postcodes, 2021 Census Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and local authority districts (LAD). Postcodes are as at May 2024 in the UK and are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. (File size 22 MB). Field Names - PCD7, PCD8, PCDS, DOINTR, DOTERM, USERTYPE, OA21CD, LSOA21CD, MSOA21CD, LADCD, LSOA21NM, MSOA21NM, LADNM, LADNMW Field Types - All Text Field Lengths - 7, 8, 8, 8, 8, 1, 9, 9, 9, 9, 55, 65, 45, 45

A best-fit lookup between enumeration postcodes, Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and local authority districts (LAD) as at 31 December 2011 in England and Wales. Postcodes are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. Enumeration postcodes are a sub-OA geography used only for the publication of estimates of males, females and households in the 2011 Census. The 2011 Census enumeration postcodes consist only of valid unit postcodes as at May 2011.

A best-fit lookup between postcodes, 2021 Census Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and local authority districts (LAD). Postcodes are as at May 2025 in the UK and are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. (File size 22 MB). Field Names - PCD7, PCD8, PCDS, DOINTR, DOTERM, USERTYPE, OA21CD, LSOA21CD, MSOA21CD, LADCD, LSOA21NM, MSOA21NM, LADNM, LADNMW Field Types - All Text Field Lengths - 7, 8, 8, 8, 8, 1, 9, 9, 9, 9, 55, 65, 45, 45

This file contains the National Statistics Postcode Lookup (NSPL) for the United Kingdom as at February 2023 in Comma Separated Variable (CSV) and ASCII text (TXT) formats. To download the zip file click the Download button. The NSPL relates both current and terminated postcodes to a range of current statutory geographies via ‘best-fit’ allocation from the 2011 Census Output Areas (national parks and Workplace Zones are exempt from ‘best-fit’ and use ‘exact-fit’ allocations).It supports the production of area based statistics from postcoded data. The NSPL is produced by ONS Geography, who provide geographic support to the Office for National Statistics (ONS) and geographic services used by other organisations. The NSPL is issued quarterly.This version has the correct Ward codes and name file in the Documents folder, as at October 2022. (File size - 184 MB).

A best-fit lookup between postcodes, frozen 2011 Census Output Areas (OA), Workplace Zones (WZ), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and current local authority districts (LAD) along with OA, WZ, and LAD classifications as at August 2019 in the UK. Postcodes are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. (File size 45MB).

A best-fit lookup between postcodes, 2021 Census Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and local authority districts (LAD). Postcodes are as at November 2025 in the UK and are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. (File size 22 MB). Field Names - PCD7, PCD8, PCDS, DOINTR, DOTERM, USERTYPE, OA21CD, LSOA21CD, MSOA21CD, LADCD, LSOA21NM, MSOA21NM, LADNM, LADNMW Field Types - All Text Field Lengths - 7, 8, 8, 8, 8, 1, 9, 9, 9, 9, 55, 65, 45, 45

A best-fit lookup between postcodes, 2021 Census Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and current local authority districts (LAD) as at May 2023 in the UK. Postcodes are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. (File size 22 MB).

A best-fit lookup between postcodes, 2021 OAs, 2021 LSOAs, 2021 MSOAs, 2022 LTLAs, 2022 UTLAs and 2022 CAUTHs. Postcodes are as at November 2023 in the UK and are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. (File size 22 MB).Field Names - PCD7, PCD8, PCDS, DOINTR, DOTERM, USERTYPE, OA21CD, LSOA21CD, LSOA21NM, MSOA21CD, MSOA21NM LTLA22CD, LTLA22NM, LTLA22NMW, UTLA22CD, UTLA22NM, UTLA22NMW, CAUTH22CD, CAUTH22NMField Types - All TextField Lengths - 7, 8, 8, 8, 8, 1, 9, 9, 55, 9, 65, 9, 45, 45, 9, 45, 45, 9, 30

This User Guide contains information about the ONSPD including: directory content; data currency; the methodology for assigning areas to postcodes; data formats; data quality and limitations and details of recent changes that have impacted on the data. Various annexes and tables provide more detailed supporting information. The download includes PDF and ODT versions of the user guide. (File size - 827 KB)

A best-fit lookup between postcodes, 2021 Census Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and local authority districts (LAD). Postcodes are as at August 2025 in the UK and are best-fitted by plotting the location of the postcode's mean address into the areas of the output geographies. (File size 22 MB). Field Names - PCD7, PCD8, PCDS, DOINTR, DOTERM, USERTYPE, OA21CD, LSOA21CD, MSOA21CD, LADCD, LSOA21NM, MSOA21NM, LADNM, LADNMW Field Types - All Text Field Lengths - 7, 8, 8, 8, 8, 1, 9, 9, 9, 9, 55, 65, 45, 45

Szukaj między kodami pocztowymi spisu powszechnego z 2011 r. dla Anglii i Walii a parafiami / wspólnotami, oddziałami i okręgami władz lokalnych na dzień 31 grudnia 2011 r. Kody pocztowe wyliczenia są geografią obszaru podwynikowego (OA) wykorzystywaną wyłącznie do publikacji szacunków dotyczących mężczyzn, kobiet i gospodarstw domowych w spisie powszechnym z 2011 r. Kody pocztowe z wyliczeniem są definiowane jako tylko te ważne jednostkowe kody pocztowe, które zostały zarejestrowane podczas spisu powszechnego w 2011 r. jako zawierające populację zwykle zamieszkałą. Kody pocztowe zostały przypisane przy użyciu metody „punkt w wielokącie”, która wykreśla średni adres każdego kodu pocztowego (centroidalny) na obszarach każdej parafii / społeczności, oddziałów i okręgów władz lokalnych (LAD). W Anglii nie ma pełnego zasięgu parafii, więc kody pocztowe spisu powszechnego z 2011 roku, które nie należą do parafii, nie będą miały przydziału parafialnego. Istnieją również 23 parafie (0,2%), które nie zawierają żadnych wyliczeń centroidów kodu pocztowego. Dzieje się tak, gdy parafia zawiera populację, ale centroid kodu pocztowego znajduje się poza parafią. W takich przypadkach nie jest możliwe przydzielenie kodu pocztowego do parafii.

Overview Water companies in the UK are responsible for testing the quality of drinking water. This dataset contains the results of samples taken from the taps in domestic households to make sure they meet the standards set out by UK and European legislation. This data shows the location, date, and measured levels of determinands set out by the Drinking Water Inspectorate (DWI). Key Definitions  AggregationProcess involving summarising or grouping data to obtain a single or reduced set of information, often for analysis or reporting purposes  Anonymisation Anonymised data is a type of information sanitisation in which data anonymisation tools encrypt or remove personally identifiable information from datasets for the purpose of preserving a data subject's privacy Dataset Structured and organised collection of related elements, often stored digitally, used for analysis and interpretation in various fields.  Determinand A constituent or property of drinking water which can be determined or estimated. DWI Drinking Water Inspectorate, an organisation “providing independent reassurance that water supplies in England and Wales are safe and drinking water quality is acceptable to consumers.”  DWI Determinands Constituents or properties that are tested for when evaluating a sample for its quality as per the guidance of the DWI. For this dataset, only determinands with “point of compliance” as “customer taps” are included.   Granularity Data granularity is a measure of the level of detail in a data structure. In time-series data, for example, the granularity of measurement might be based on intervals of years, months, weeks, days, or hours ID Abbreviation for Identification that refers to any means of verifying the unique identifier assigned to each asset for the purposes of tracking, management, and maintenance.  LSOA Lower-Level Super Output Area is made up of small geographic areas used for statistical and administrative purposes by the Office for National Statistics. It is designed to have homogeneous populations in terms of population size, making them suitable for statistical analysis and reporting. Each LSOA is built from groups of contiguous Output Areas with an average of about 1,500 residents or 650 households allowing for granular data collection useful for analysis, planning and policy- making while ensuring privacy.  ONS Office for National Statistics  Open Data Triage The process carried out by a Data Custodian to determine if there is any evidence of sensitivities associated with Data Assets, their associated Metadata and Software Scripts used to process Data Assets if they are used as Open Data.  Sample A sample is a representative segment or portion of water taken from a larger whole for the purpose of analysing or testing to ensure compliance with safety and quality standards.  Schema Structure for organizing and handling data within a dataset, defining the attributes, their data types, and the relationships between different entities. It acts as a framework that ensures data integrity and consistency by specifying permissible data types and constraints for each attribute.  Units Standard measurements used to quantify and compare different physical quantities.  Water Quality The chemical, physical, biological, and radiological characteristics of water, typically in relation to its suitability for a specific purpose, such as drinking, swimming, or ecological health. It is determined by assessing a variety of parameters, including but not limited to pH, turbidity, microbial content, dissolved oxygen, presence of substances and temperature. Data History Data Origin  These samples were taken from customer taps. They were then analysed for water quality, and the results were uploaded to a database. This dataset is an extract from this database. Data Triage Considerations Granularity Is it useful to share results as averages or individual? We decided to share as individual results as the lowest level of granularity Anonymisation It is a requirement that this data cannot be used to identify a singular person or household. We discussed many options for aggregating the data to a specific geography to ensure this requirement is met. The following geographical aggregations were discussed: • Water Supply Zone (WSZ) - Limits interoperability with other datasets • Postcode – Some postcodes contain very few households and may not offer necessary anonymisation • Postal Sector – Deemed not granular enough in highly populated areas • Rounded Co-ordinates – Not a recognised standard and may cause overlapping areas • MSOA – Deemed not granular enough • LSOA – Agreed as a recognised standard appropriate for England and Wales • Data Zones – Agreed as a recognised standard appropriate for Scotland Data Triage Review Frequency  Annually unless otherwise requested Publish Frequency Annually Data Specifications • Each dataset will cover a year of samples in calendar year • This dataset will be published annually • Historical datasets will be published as far back as 2016 from the introduction of The Water Supply (Water Quality) Regulations 2016 • The determinands included in the dataset are as per the list that is required to be reported to the Drinking Water Inspectorate. • A small proportion of samples could not be allocated to an LSOA – these represented less than 0.1% of samples and were removed from the dataset in 2023. • See supplementary information for the lookup table applied to each calendar year of data. Context Many UK water companies provide a search tool on their websites where you can search for water quality in your area by postcode. The results of the search may identify the water supply zone that supplies the postcode searched. Water supply zones are not linked to LSOAs which means the results may differ to this dataset. Some sample results are influenced by internal plumbing and may not be representative of drinking water quality in the wider area. Some samples are tested on site and others are sent to scientific laboratories. Supplementary information Below is a curated selection of links for additional reading, which provide a deeper understanding of this dataset.   1. Drinking Water Inspectorate Standards and Regulations: https://www.dwi.gov.uk/drinking-water-standards-and-regulations/   2. LSOA (England and Wales) and Data Zone (Scotland): https://www.nrscotland.gov.uk/files/geography/2011-census/geography-bckground-info-comparison-of-thresholds.pdf   3. Description for LSOA boundaries by the ONS: https://www.ons.gov.uk/methodology/geography/ukgeographies/censusgeographies/census2021geographies4. Postcode to LSOA lookup tables (2022 calendar year data): https://geoportal.statistics.gov.uk/datasets/3770c5e8b0c24f1dbe6d2fc6b46a0b18/about5. Postcode to LSOA lookup tables (2023 calendar year data): https://geoportal.statistics.gov.uk/datasets/b8451168e985446eb8269328615dec62/about6. Postcode to LSOA lookup tables (2024 calendar year data): https://geoportal.statistics.gov.uk/datasets/068ee476727d47a3a7a0d976d4343c59/about7. Legislation history: https://www.dwi.gov.uk/water-companies/legislation/

Overview

Water companies in the UK are responsible for testing the quality of drinking water. This dataset contains the results of samples taken from the taps in domestic households to make sure they meet the standards set out by UK and European legislation. This data shows the location, date, and measured levels of determinands set out by the Drinking Water Inspectorate (DWI).

Key Definitions

Aggregation

Process involving summarizing or grouping data to obtain a single or reduced set of information, often for analysis or reporting purposes

Anonymisation

Anonymised data is a type of information sanitization in which data anonymisation tools encrypt or remove personally identifiable information from datasets for the purpose of preserving a data subject's privacy

Dataset

Structured and organized collection of related elements, often stored digitally, used for analysis and interpretation in various fields.

Determinand

A constituent or property of drinking water which can be determined or estimated.

DWI

Drinking Water Inspectorate, an organisation “providing independent reassurance that water supplies in England and Wales are safe and drinking water quality is acceptable to consumers.”

DWI Determinands

Constituents or properties that are tested for when evaluating a sample for its quality as per the guidance of the DWI. For this dataset, only determinands with “point of compliance” as “customer taps” are included.

Granularity

Data granularity is a measure of the level of detail in a data structure. In time-series data, for example, the granularity of measurement might be based on intervals of years, months, weeks, days, or hours

ID

Abbreviation for Identification that refers to any means of verifying the unique identifier assigned to each asset for the purposes of tracking, management, and maintenance.

LSOA

Lower-Level Super Output Area is made up of small geographic areas used for statistical and administrative purposes by the Office for National Statistics. It is designed to have homogeneous populations in terms of population size, making them suitable for statistical analysis and reporting. Each LSOA is built from groups of contiguous Output Areas with an average of about 1,500 residents or 650 households allowing for granular data collection useful for analysis, planning and policy- making while ensuring privacy.

ONS

Office for National Statistics

Open Data Triage

The process carried out by a Data Custodian to determine if there is any evidence of sensitivities associated with Data Assets, their associated Metadata and Software Scripts used to process Data Assets if they are used as Open Data. <

Sample

A sample is a representative segment or portion of water taken from a larger whole for the purpose of analysing or testing to ensure compliance with safety and quality standards.

Schema

Structure for organizing and handling data within a dataset, defining the attributes, their data types, and the relationships between different entities. It acts as a framework that ensures data integrity and consistency by specifying permissible data types and constraints for each attribute.

Units

Standard measurements used to quantify and compare different physical quantities.

Water Quality

The chemical, physical, biological, and radiological characteristics of water, typically in relation to its suitability for a specific purpose, such as drinking, swimming, or ecological health. It is determined by assessing a variety of parameters, including but not limited to pH, turbidity, microbial content, dissolved oxygen, presence of substances and temperature.

Data History

Data Origin

These samples were taken from customer taps. They were then analysed for water quality, and the results were uploaded to a database. This dataset is an extract from this database.

Data Triage Considerations

Granularity

Is it useful to share results as averages or individual?

We decided to share as individual results as the lowest level of granularity

Anonymisation

It is a requirement that this data cannot be used to identify a singular person or household. We discussed many options for aggregating the data to a specific geography to ensure this requirement is met. The following geographical aggregations were discussed:

<!--·
Water Supply Zone (WSZ) - Limits interoperability with other datasets

<!--·
Postcode – Some postcodes contain very few households and may not offer necessary anonymisation

<!--·
Postal Sector – Deemed not granular enough in highly populated areas

<!--·
Rounded Co-ordinates – Not a recognised standard and may cause overlapping areas

<!--·
MSOA – Deemed not granular enough

<!--·
LSOA – Agreed as a recognised standard appropriate for England and Wales

<!--·
Data Zones – Agreed as a recognised standard appropriate for Scotland

Data Specifications

Each dataset will cover a calendar year of samples

This dataset will be published annually

Historical datasets will be published as far back as 2016 from the introduction of of The Water Supply (Water Quality) Regulations 2016

The Determinands included in the dataset are as per the list that is required to be reported to the Drinking Water Inspectorate.

Context

Many UK water companies provide a search tool on their websites where you can search for water quality in your area by postcode. The results of the search may identify the water supply zone that supplies the postcode searched. Water supply zones are not linked to LSOAs which means the results may differ to this dataset

Some sample results are influenced by internal plumbing and may not be representative of drinking water quality in the wider area.

Some samples are tested on site and others are sent to scientific laboratories.

Data Publish Frequency

Annually

Data Triage Review Frequency

Annually unless otherwise requested

Supplementary information

Below is a curated selection of links for additional reading, which provide a deeper understanding of this dataset.

<!--1.
Drinking Water Inspectorate Standards and Regulations:

<!--2.
https://www.dwi.gov.uk/drinking-water-standards-and-regulations/

<!--3.
LSOA (England and Wales) and Data Zone (Scotland):

<!--4. https://www.nrscotland.gov.uk/files/geography/2011-census/geography-bckground-info-comparison-of-thresholds.pdf

<!--5.
Description for LSOA boundaries by the ONS: Census 2021 geographies - Office for National Statistics (ons.gov.uk)

<!--[6.
Postcode to LSOA lookup tables: Postcode to 2021 Census Output Area to Lower Layer Super Output Area to Middle Layer Super Output Area to Local Authority District (August 2023) Lookup in the UK (statistics.gov.uk)

<!--7.
Legislation history: Legislation - Drinking Water Inspectorate (dwi.gov.uk)

Μια καλύτερη αναζήτηση μεταξύ των ταχυδρομικών κωδίκων, τις παγωμένες περιοχές παραγωγής απογραφών 2011 (OA), τις περιοχές υπερπαραγωγής κατώτερης στρώσης (LSOA), τις περιοχές υπερπαραγωγής μέσης στρώσης (MSOA) και τις τρέχουσες περιφέρειες τοπικής αυτοδιοίκησης (LAD) όπως στο στυλ

A best-fit lookup between postcodes, frozen 2011 Census Output Areas (OA), Lower Layer Super Output Areas (LSOA), Middle Layer Super Output Areas (MSOA) and current local authority districts (LAD) as at srpen 2021 ve Spojeném království. Poštovní směrovací čísla jsou nejlépe vybavena vynesením umístění střední adresy poštovního směrovacího čísla do oblastí výstupních zeměpisných oblastí. (Velikost souboru 24 MB).