You have a seven year old car.
Just the corrosion getting ground into the pads when you drive it will warp the rotors.
For the cost of rotors, why would you not change them?

As to the water on rotors question:
All the brake safety engineers in the industry would crackup over the question.
They are designed for natural weather conditions, which includes flooding and hard spray.
Yes, they do not last forever; they are not designed to...
These cars are made to DRIVE, not be a garage trophy.

__________________
ASE Master Mechanic

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D

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