Do insurance companies consider a vehicle a total loss if it has been submerged in a lake?

I guess if you had the choice of where to submerge your vehicle, a lake would be the best place. Lakes are usually fresh water and relatively clean; relative to, say, flood waters. But fully or even partially submerged vehicles are NEVER the same after they are recovered, dried out, and cleaned up, especially if they were submerged in salt or filthy water. Some companies will "total" a car that has been immersed in salt or flood waters. When it has been submerged in fresh water, however, totaling depends upon the value of the car: if the remediation costs more than the car is worth, they will total it.