January 2026

This release note provides information about the January 2026 release of OS MasterMap Water Network Layer.

Feature counts

Feature Type	Count
WatercourseLink	5 027 435
HydroNode	4 902 543

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

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 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.

Final release

No further releases scheduled

The January 2026 OS MasterMap Water Network release will be the final publication with no further releases scheduled. Please see End of Life notice above for further details.