USB Implementers Forum(The group responsible for maintaining and promoting USB standards) launched version r2.3 of the USB Type-C Cable and Connector Specification a couple of months ago. It has an interesting new feature addition giving manufacturers the freedom to create a new liquid detection pin in the standard USB Type C connector. Although the standard doesn’t mandate the exact location placement of the new pin/pads it gives general guidelines of where it can be placed. Check images. The two variations are a full-width pad running the entire length of the USB receptacle and the other being two small pads next to the VBUS and CC pins. The second one is placed in the areas where liquid corrosion is mostly found in the connectors. It will be present in both orientations.
Why is this a reasonably big deal? USB Type C connector is most likely going to be the single most common connector for virtually all human interaction interfaces for the next decade. A common failure point of this connector is liquid damage due to spilled water, coffee, sweat, falling in water etc. The liquid forms a bridge between the pins and when power is applied(5V or the higher voltage modes USB Fast chargers support) exposed metal will dissolve into free ions and these ions will migrate from one pin to another. This will form an oxide layer and it will create the greenish stuff you find when there is corrosion. These lead to improper connections or open circuits that will ruin the connector. With the new liquid detection pin, they’ve made some changes to the USB protocol standard. Now, when liquid is detected(via impedance or leakage measurement), the controller won’t turn on the USB power switch for that pin. It will even show a software error as a reminder to clean the port. No power means no electrolysis or corrosion. So, your connector stays in top shape. Apple is already doing this with the type C connectors in iPhones. Thumbs up to them!
