The 8.5 km (5.3 mi) lower part between the Elbe and Uetersen is navigable for Class II ships, the 10.3 km (6.4 mi) middle part between Uetersen and Pinneberg is navigable but not classified.

[1] The Pinnau has its source in the town of Henstedt-Ulzburg, then flows southwest, in Pinneberg to the west and ends in the municipality of Haselau in the Elbe, which streams in northwestern direction.

The Pinnau is very much tide dependent and strongly influenced by tidal range.

The Pinnau is a federal waterway within the remit of the Wasserstraßen- und Schifffahrtsamt Hamburg [de] (Waterways and Shipping Office Hamburg) from the south-western edge of the railway bridge in Pinneberg to the mouth of the Pagensander Nebenelbe with 18.81 km (11.69 mi), at Elbe-km 658.99.

It is one of the inland waterways, on which the German Seeschifffahrtsstraßen-Ordnung [de] (Maritime Traffic Regulations) applies.