I'm assuming that your flooded basement was full of salt water which is very conductive and could cause problems if it soaked into the insulation of an electric hot water heater. It is also corrosive and might cause problems that don't show up immediately. I would go for a new panel w/new breakers just to be on the safe side. If your local code says 200 amps by all means, use the 200 amp as it saves money down the road if you ever add more electric appliances like air conditioning, a heat pump, or electric heat.
As I said at the start my information is over ten years old, so unless you have a brother-in-law in the business expect to spend over $2,000.00...Flood insurance??
Regards,
GtG
Thanks everyone for the info.