October 2025

This release note provides information about the October 2025 release of OS MasterMap Water Network Layer.

Feature counts

Feature Type	Count
WatercourseLink	4 861 007
HydroNode	4 875 314

Errors

Error Type	Count
Links with spikes	0
Single link loops	48
Multi-link circular flow loops that include River Links	4
Multi-link circular flow loops on Drains	29

Product improvements

Details of live and resolved data issues for the OS MasterMap Water Layer product will be communicated on the OS MasterMap Water Network Layer Known Data Issues page. This page will provide details of their impacts and updates on the expected time frame for their resolution.

Notices

OS MasterMap Water Network Layer product will soon become End of Life

The OS MasterMap Water Network Layer product will become End of Life on 31 March 2026. As of this date, Ordnance Survey will cease to maintain or publish updates, and access to the product will be removed from the OS Data Hub, OS Features API and OS Vector Tile API.

We recommend you migrate to using the data in the OS NGD Water Network Collection as it contains very similar data content to OS MasterMap Water Network Layer – ​see the Comparison of Water Network Products page page for a full comparison of the data supply, available formats, and attribution between the two products.

Further information can be found on the End of Life Notice – OS MasterMap Water Network Layer page.

Next release

The next release of OS MasterMap Water Network Layer is scheduled for January 2026.

The January 2026 release will be the final release of OS MasterMap Water Network Layer.