5 - 30 minutes
I'm pretty sure there was salt water damage to my phone. It was in my side pocket when I hauled my boat out of the water after a 21 day trip in Barkley Sound. I'd kept the phone in a waterproof pouch all that time, then had it out at the end while I was unloading and I guess my legs were deeper in the water than I'd realized. After hauling the boat the phone wouldn't power on.
I got the phone in rice the next day and a few days later ordered the battery replacement kit. When it arrived, I took the phone apart & cleaned everything with isopropyl alcohol then put it back together. It powered on!! Miraculous. Except that the charging port wasn't working. The phone wouldn't charge or allow me to download image to my computer. I spent a few hours trying to send myself images, one at a time, by text or email. Then the phone died again. So now, I'm going to try it all again and take the charging port out & clean all that and maybe replace that if I have to. I'd really love to have the images of my trip.
Now I know to wash the phone with fresh water and then with alcohol straight away and to not power it on and to take the battery asap. If you've got water damage, esp salt water, it makes sense to disassemble it completely, including the charging port, while it's open and you're deep into it.