Firefighters were called to flooding on Headstone Drive in Wealdstone.
A water main under a railway bridge burst causing flooding to a depth of 1m. Crews assisted two men from a vehicle. There were no reports of any injuries.
The Brigade was called at 0811 and the incident was over for firefighters by 0916. Two fire engines from Harrow and Stanmore fire engines and two fire rescue units from Wembley and Heston fire stations attended the scene.