While H3 is parked on driveway, driver floor mat is removed, and steering turned all the way right to expose splash area, pressure hose the front left steering splash area behind left tire while another person feels with their hands to determine where water is entering. If the leak is beneath, it would only enter when you go through flooded area. When it rains, the water constantly splashes behind the tires, which is an area source for water to enter the driver area while the vehicle is in motion during rain condition. If you live in snow area, they use salt to keep roads clear of snow. Salty water is highly corrosive to exposed steel. In the summer or fall season before snow begins, you steam jet pressure clean the underside, then inspect for any area where undercoating had come off. Take primer spray paint and cover these exposed areas with at least 3 coats of primer paint, or rubber sealant spray.