DIY Repair your SONOS devices! YES WE CAN!

The most immediate step is to remove power and disconnect all wires. As noted above, be aware of personal safety if the area is wet.

If the unit is powered during the flood, there could be massive damage due to stray conductive paths. If the unit was more or less fully wet, rinse the unit with clean water. Impure water can result in chemical ractions that will corrode metals -- causing them to disappear into a green mess. Sugary drinks are very destructive. Fully dry the unit as soon as possible.

Note that SONOS will not repair a unit that has been opened. If you have decided to DIY, then continue.

Open the unit and, if it had been thoroughly wet, give it another flush and dry. Clear water in an unpowered unit is not much of an issue. One should see what happens on the production line -- there are all sorts of nasty liquids. Try not to flush debris into controls and switch contacts. Thoroughly dry the unit.

I don't recommend applying power until the internals have been given a thorough flush and visual inspection. Look for deposits and mechanical issues. Now, you can power the unit and fully assess the damage, if any.

You'll need to be capable of component level diagnosis and repair because there are no complete assemblies available. Things can become very complicated if you need to replace any of the FLASH RAM because you'll need to program the replacement.

I'd recommend distilled water for rinsing the system, no minerals in it to leave behind when it evaporates.

Once rinsed low pressure compressed air or canned air (warm it often) will do to remove the water. Pay particular attention to the spaces under components, get them very dry.

There are repair posts around here with parts sources and tips but you'll have to dig for them. If the forum search fails try a real search engine and restrict it to just this site.

Unless the liquid is grossly caustic or acidic, relatively brief exposure to a liquid is not much of an issue (assuming that the unit is not powered), it's what the liquid leaves behind after evaporation that can cause trouble. Sugary liquids (especially soda -- which usually contains phosphoric acid) evaporating will leave their sugar behind. Over time this coating will use water from the atmosphere to form acids that will eat away the metal -- many months after the original exposure. I've seen boards where the printed circuit traces and some smaller components were gone -- converted to a sticky green mess. After the original spill and casual drying, it seemed like the unit was working and the user claimed victory. Months later the unit failed and repair was not practical. Proper flush after the spill would have saved the unit.

Stanley_4's comment about using compressed air to remove the water is helpful. Mechanical removal of the water is better than evaporation. Pay attention to the low pressure comment. High pressure blasts can blast components off of the board along with the water.