> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/products/water-portfolio.md).

# Water Portfolio

## Water products

This portfolio provides data on water bodies, tidelines and river networks across Great Britain. Its topographic water features and structured network models allow you to visualise, analyse and manage aquatic environments. The products support environmental monitoring, flood modelling, infrastructure planning and ecological research use cases.

The following downloadable products are available within the Water Portfolio:

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-cover data-type="image">Cover image</th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><h3>OS MasterMap Topography Layer</h3></td><td>A detailed and accurate view of the landscape of Great Britain, representing both the manmade and natural environment, with over 500 million real-world objects.</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS MasterMap Topography Layer product data over a background map."><a href="/files/RbaIlv1od5VoWn7ZwQg6">/files/RbaIlv1od5VoWn7ZwQg6</a></td><td><a href="/pages/Ypr2EuVZztjY9SGZiR5M">/pages/Ypr2EuVZztjY9SGZiR5M</a></td></tr><tr><td><h3>OS Open Linked Identifiers</h3></td><td>An open dataset of cross-referenced identifiers detailing relationships between Unique Property Reference Numbers (UPRNs), Unique Street Reference Numbers (USRNs) and Topographic Identifiers (TOIDs).</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS Open Linked Identifiers product data over a background map."><a href="/files/EzPhnr4lQxZl1U4yH4YI">/files/EzPhnr4lQxZl1U4yH4YI</a></td><td><a href="/pages/E75anmH6Gzr8espw2gGg">/pages/E75anmH6Gzr8espw2gGg</a></td></tr><tr><td><h3>OS Open Rivers</h3></td><td>An open dataset providing a high-level view of over 144 000km of water bodies and watercourses in Great Britain.</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS Open Rivers product data over a map of Great Britain."><a href="/files/fOgRC9aSQJYCQH6dGHKe">/files/fOgRC9aSQJYCQH6dGHKe</a></td><td><a href="/pages/Gv9sGinz2kXt9k40XTnE">/pages/Gv9sGinz2kXt9k40XTnE</a></td></tr><tr><td><h3>OS Open TOID</h3></td><td>An open dataset of unique identifiers for landscape and built environment features with a generalised location extracted from OS MasterMap products.</td><td></td><td data-object-fit="cover" data-alt="Example image showing OS Open TOID product data over a background map of an urban area."><a href="/files/x1raWSxuMX7hcmcZ3Fl0">/files/x1raWSxuMX7hcmcZ3Fl0</a></td><td><a href="/pages/3n6n67RdCpniEPsa9Nci">/pages/3n6n67RdCpniEPsa9Nci</a></td></tr></tbody></table>

{% hint style="info" %}

### OS MasterMap Water Network Layer

The OS MasterMap Water Network Layer product (also referred to as OS MasterMap Networks – Water Layer) was withdrawn on 31 March 2026. As of this date, Ordnance Survey will no longer maintain or publish updates to the product. Documentation for the product can be found in the [End of Life Product Documentation section](/os-downloads/resources/product-resources/end-of-life-product-documentation.md) for the 12 months that data packages and download orders remain available on the OS Data Hub for existing customers.
{% endhint %}


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