Android developers are the best. Watch them for long enough, and they’ll come up with tools that you didn’t even know were possible. For example, this little app claims it can tell you whether the water-resistant seals in your phone are still intact. Water Resistance Tester is a free download in the Play Store.
Developer Ray W uses data from the barometric pressure sensor that’s now built into most high-end phones as an aid to vertical location determination. Minute differences in that pressure can help test, with a varying degree of accuracy, whether the ingress protection seals built into a phone with an IP rating are still intact.
The test asks the user to leave the phone alone for a moment, then press firmly down on two points of the screen. By measuring pressure differences, it says it can tell if the seals are still reliable. It should work on any phone with an IP rating, and it can adapt to physical changes — you can test it yourself by popping out your SIM card tray, which should return a negative result even after the app has given a seal approval previously.
Ray W makes no guarantees in the app, and the results probably won’t sway a company that’s decided it doesn’t want to honor a warranty. So you probably shouldn’t use this as an all-clear to dunk a device, especially if it’s on the older side.
But the current results from users are impressive. Play Store reviews note that phones without a factory IP rating indeed return a negative result, and those that had protection but had a screen repair report the seals are no longer functional. The Water Resistance Tester app is free with minimal ads. A $.99 donation removes them, but you can be more generous if you like.