My iphone wont charge because it says it detects liquid. I dried it out and it works sometimes but not others.

Consider this article for help.

So when you see one of the [Detected Liquid] alerts, your iPhone has detected liquid in the Lightning port or on the Lightning cable or Lightning accessory. To protect your iPhone, charging and accessory connection are unavailable until the charger is dry.

Suppose you see this alert whenever you connect a specific cable or accessory. In that case, that cable might be damaged. Contact the manufacturer.

If you see this alert every time you connect an Apple Lightning cable or accessory, contact Apple Support.

About how long was the phone under water?