I dropped my iPhone 6s in a sink filled with water, but it's perfectly fine?

I dropped my iPhone 6s in a sink filled with water, but it seems perfectly fine. I grabbed it out right away, so it was only submerged for about 5 seconds. I dried it off, and the excess water dripped out from the speaker, headphone jack, and charger slot. The speakers work, it can hold a charge, and the headphone jack works with my earbuds. I'm just wondering if there are any precautions I should take to avoid water damage problems with my iPhone in the future?