Careless iPhone owners who’ve submerged their handsets in some form of liquid can now take Apple up on an unadvertised policy that offers replacements for a flat fee of $199.

According to several sources, the new policy pertains to out-of-warranty incidents that would normally require the purchase of a new phone, but does so at the expense of triggering an extention of the owner’s two-year AT&T wireless service contract.

Customers who trade-in their water damaged phones will be given a factory refurbished model — not a new iPhone — and can then transfer the SIM card from their damaged handset into the refurbished device.

Apple began including liquid submersion indicators, or LSIs, in its portable products around the time it introduced its first iPhone. They irreversibly change color once they come in contact with a liquid, thereby offering the company’s retail store staff and authorized repair specialists an easy way to determine if a customer caused damage to their product with liquids — incidents that aren’t covered under Apple’s standard warranties.

Speculation is that Apple’s policy change on water-damaged iPhones could be a means of clearing out inventory of the current iPhone 3G ahead of new models expected this summer. However, an informed commenter points out that it’s more likely an easing of general policy given that offer is valid for first-generation iPhones and costs $199 regardless of the generation or capacity of the iPhone.