Agree with Ray that if it was seawater it is a loss. The only approach if something is immersed in salt water is immediately flushing it with a large volume of fresh water and given your local water using distilled for this task ranges from advisable through mandatory. "Tap" water and well water (potentially worse after softening depending upon the method) can be nearly as bad as sea water.
When something gets soaked, immediately pull the battery and if the water is suspected of having a significant mineral content I would then flush with distilled water before drying. Adding even more water to a submerged camera body or lens may seem risky but once soaked additional water isn't going to do any additional damage and it will remove residue from the original less than pure water source.
Initial fast drying should be done with a gently heated air stream, a "space" heater works well for this phase. Followup by putting the device in a sealed bag with a desiccant, I really don't like using rice which isn't nearly as effective as the real thing and can create problems. I have some large desiccant packs that were used when storing military gear, many Pelican cases also come with similar packs and they are reusable by gently heating to drive the moisture out. The military units and better commercial packs are color coded and change color as the moisture content goes up. If your camera or lens gets really wet then drying will overwhelm even large desiccant packs so you will need at least two to cycle between.
All of this is a pain so avoidance is best. I restore vintage amateur radio gear and in a few cases I have given radio gear a complete bath (for example a pretty rare RCA commercial communications receiver from the mid 1930s I restored last year). It had been stored and mice had move in so it got a thorough outside bath with disinfectant while I wore a mask followed by multiple distilled water rinses (and I use deionized water when dealing with anything where it has insulation dealing with voltages over 1,000 volts). It then dried in the sun with forced air ventilation followed by hot air and finally desiccant. After a complete restoration it worked as well as it did brand new but it was a lot of work and had it not been rare I wouldn't have taken on the project.
In general, I wouldn't touch a camera or lens that required this level of work because even if returned to functionality its reliability is forever compromised (both mechanically and electronically) and even if you aren't a pro photographer you still don't want to be reliant upon something with a greatly increased chance of failure. A DSLR still has a complex shutter mechanism that relies upon proper lubricant in parts of that assembly which will be compromised by water so even if the electronics survive, the shutter mechanism is suspect and should be replaced. In many cases this will dictate that it is far better to replace the camera-the same reason that flood damaged vehicles are sold with salvage titles and are nearly worhtless on the open market excpet for their parts value.
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
