Do not even think about it
The number of drivers that are risking their lives, the lives of others, including emergency service personnel, and their vehicles by driving into flooded roads is of increasing concern.
Some insurers have in fact started to include an exclusion in their policy refusing to indemnify for such losses which can be substantial.
I support this in an effort to have people understand the personal risk they are taking but struggle where someone does it by accident, say driving along an unfamiliar remote country road at night.
You can check who has introduced this exclusion by visiting LMI PolicyComparison.com.
Whether you are insured or not for this risk, my strong advice is do not even think about driving across any flooded roadway.