Why is my iPhone waking up every 10 seconds?

I'm going to go ahead and guess you've already turned the phone off and on and again, and after that, you tried resetting your phone?

It happened to me too after i upgraded my iphone 6s to iOS 10. They have a new feature called 'raise to wake' which wakes your screen up so you can see the date and time quickly. You can turn this off by going into 'settings' -> 'display and brightness' then toggle 'raise to wake' off.

Mines turns on and off randomly with raise to wake off I even turned on do not disturb but it still does it

My raise to wake is turned off but the phone still lights up

A water damaged iphone needs to be taken apart and the logicboard shields have to be taken off to water treat the iphone into pure alcohol as it will cause more problems down the line as corrosion sets in ,goodluck