A method for measuring a liquid volume and/or corresponding fill rate of floating roof tanks includes selecting an Area Of Interest (AOI) to be monitored at the earth's surface, gathering geographical coordinates of tanks in the AOI, and downloading and pre-processing a time series of SAR reference images covering the AOI. The method includes projecting geographical coordinates of the tanks on the time series of the images to determine pixel coordinates of the tanks, and determining tank dimensions through processing of the images at the pixel coordinates. The method includes downloading and pre-processing at least one new SAR image over the AOI and registering it on top of the reference images, and, for each tank of the AOI, detecting in the new SAR image a bright spot corresponding to the roof of the tank and converting its pixel coordinates into liquid volume and/or fill rate information.