Arrange for an inspection and test to be carried out on the property. The registered electrician will issue you with an Electrical Installation Condition Report (EICR) which will identify the condition of the wiring and equipment in need of repair.
All of the portable appliances affected by the flood will need to be tested to make sure that they are safe for continued use, as well as fixed equipment such as electric cookers.
If the water damage to electrics is relatively minor and caused by clean water, i.e. a burst water pipe or tank, then it is likely that the registered electrician will just need to dry out cables and replace any accessories affected by the water (sockets, switches, plugs etc.)
If there is major flood damage to the electrics caused by clean or contaminated water, then it is likely that parts of the electrical installation will need to be rewired.
When rewiring is necessary, ask the registered electrician about the possibility of raising the height of the newly installed electrical equipment, including raising the fuse box and sockets to above any future expected flood level.
Remember………….Keep safe out there.