https://news.samsung.com/global/fac...alaxy-s7-and-s7-edge-water-and-dust-resistant
According to the video in this post from the official Samsung newsroom, the S7/S7 Edge is not ONLY tested according to IP68, but also IPX1, IPX2 and IPX5. So it should be able to handle pouring water and water jets. The engineers in the interview say this regarding use under water: "We would recommend against using the phones for longer periods of time under high-pressure water taps, or in the ocean or other saltwater environments." They also say: "It won’t present any problems if you use these devices under fresh water for a short time, but it is recommended that you do so according to the product specifications." So, Samsung are actually telling people, via their official channels, that it is OK to use the device under water, but not under "high pressure" taps.
Also, these official videos from Samsung Indonesia and Samsung Malaysia make it pretty clear they encourage you to use the water resistance as a feature allowing you to take cool photos/videos in wet environments, and not just see it as a protection against accidents, right?
https://youtu.be/6bNv51boLtk
https://youtu.be/mvWslN5DIHM
The only disclaimer in these videos is "individual results may vary"
I'd say these videos are very bold, and they use the devices in ways that present quite a lot of water pressure. If they encourage these situations, I'd say it should be able to handle the OP's gentle tap water rinse with no issues.
In addition to these videos there are numerous commercials already mentioned, where Samsung show that it is OK to use the device in water.
Personally, I think these videos are too brave from Samsung and they are surely gonna lead to many people ruining their brand new devices. I think we should be more careful than that
That being said, I've had the Xperia V and Xperia Z3 and used these A LOT under water, diving headfirst into pools and the ocean and rinsing them regularly under the tap. And they have lower certification than the S7/S7 Edge. Never any problems, even after the glass back of the Z3 was cracked it never failed the water resistance.