Home Button Periodically Stops Working

My home button will work but then the next day will be completely unresponsive. Even weirder, Siri constantly keeps turning on and interrupting me as well as apps closing to the home screen and the device jumping into multitasking mode. It seems as if the home button works to a degree and now has a mind of its own. I did accidentally submerge the phone in water. Everything else works and the home button worked fine for a month or two but now it freaks out often. So the home button isn't completely broken but isn't completely fine either. My theory is that there may be just some water stuck in the home button assembly or that some of the wires have become touchy due to the water damage. Unfortunately, water damage voids Apple's warranty and, as I have discovered, most phone repair shops.

So what would be the best course of action and, if possible, would I be able to fix it myself?