What safety precautions should i take when entering in a flooded area?

i have a Toyota gasoline type AUV and Isuzu diesel pickup. What safety precautions should i take to avoid knocking out my engine.
1) What part of engine should not get wet in gasoline and diesel?
2) What is the best engine type is best to use in flooeded area?
3) what is the allowable depth of water should i take in to, is waist line level still allowed for a vehicle to enter?

Thank you guys!

Are There Any Gas Limits In Your Area? Also What Are You Paying Per Gallon?

I live in New York City , gas is around 3.74-4.00 depending on were you go and there doesn’t seem to be much of a shortage. I keep reading reports of people being limited to dollar or gallon amounts.
Where do you live and is this happening in your area? I think it’s unfair for cities to be swallowing gasoline like water while the rest of the country is limited like this.