A:AnswerUnder "Features" it states water resistance is not "permanent and can diminish with time". My last watch, about 2 yrs old died in my swimming pool.
A:AnswerThe battery life should last longer than 1 day, especially if brand new. Mine can go about 20 hours without needing a charge. Check out your system settings and disable things like background app refresh. This will save on your battery life. If this doesn’t work, reach out to Apple for a replacement