How to Check a Used Phone for Water Damage (iPhone & Android)
How to check a used phone for water damage: find the liquid contact indicator in the SIM tray, spot corrosion and hidden signs, and run tests on iPhone and Android.
iSerial TeamUpdated · 5 min read
In this article
Water damage is the used-phone problem that hides best. A phone that took a swim can dry out, power on and pass a quick look perfectly — then start dropping calls, refusing to charge or losing Face ID a few weeks later as corrosion slowly eats the board. Many sellers genuinely don’t know their phone was damaged; some know very well.
You can’t open a phone in a car park, but you can catch most liquid damage with a flashlight, five minutes of testing and a records check. This guide shows you where the indicators are, what corrosion looks like, which functions fail first, and how to make a decision when the evidence is mixed.
Why water damage is so hard to spot
Modern phones are water resistant, not waterproof. The adhesive seals that give a phone its IP rating weaken with age, heat and any screen or battery repair. Once liquid gets in, the immediate effect is often nothing at all. The real damage comes later, as minerals and salt left behind cause corrosion on connectors and tiny components. Salt water, pool water and sugary drinks are far worse than a quick dunk in clean water.
That delay is why a “works perfectly” demonstration isn’t enough. You’re looking for evidence that liquid got in, plus early symptoms that the corrosion has started.
Step 1: Find the liquid contact indicator (LCI)
Most phones contain small liquid contact indicators — stickers that are white or silver when dry and turn red or pink permanently when they touch water or a water-containing liquid. Manufacturers use them when deciding whether a repair is covered by warranty.
iPhone
On iPhones with a SIM tray, Apple places an LCI inside the SIM tray slot. Use the SIM tool to eject the tray, then shine a bright flashlight into the slot and look slightly to one side — the indicator is a small dot or strip on the inner wall.
- White or silver: no liquid contact recorded at that spot.
- Red or pink: the indicator has been triggered. Treat the phone as liquid-damaged.
US iPhone 14 and later have no SIM tray, so the indicator can’t be seen without opening the phone. On those models, the other steps in this guide carry more weight. Apple describes its indicators in its support articles on support.apple.com.
Android
Placement varies by brand and model. Many Android phones have an indicator in or near the SIM slot, others only inside the body near the battery. Older phones with removable backs usually had a sticker on the battery or under it. If you can’t find one, don’t assume the phone is clean — move on to the next steps.
Step 2: Look for corrosion and physical clues
With the flashlight still out, inspect these areas closely:
- Charging port. Green, white or crusty deposits on the pins, or a dull, discolored look. Lint is normal; chalky residue is not.
- SIM tray and slot. Rust spots on the metal tray or discoloration on the SIM contacts.
- Speaker and microphone grilles. Residue or a stained mesh.
- Camera lenses. Fog, droplets or a hazy film inside the lens is a classic sign of moisture inside the body.
- The screen. Faint blotches, bright spots, shadowy patches or lines can be caused by liquid under the display.
- Screws and seams. Damaged screws near the port, or a screen that sits slightly raised, suggest the phone has been opened — sometimes to dry it out.
Step 3: Run the functional tests
Liquid tends to attack certain parts first. Test each of these, ideally with your own SIM and cable:
- Charging. Plug in with a known-good cable. Charging should start immediately and stay connected when you wiggle the cable gently.
- Speakers and mics. Play a video at full volume — crackling or a muffled sound is a warning sign. Record a voice memo and a video with each camera, then play them back.
- Calls. Make a call on speaker and on the earpiece; the other person should hear you clearly.
- Face ID / fingerprint. Set up a new face or fingerprint. On iPhone, “Face ID is not available” after a phone has been wet is a common symptom.
- Buttons and touch. Press every button repeatedly. Draw slowly across the whole screen in a notes app to find dead zones or “ghost touches”.
- Wireless. Turn Wi-Fi and Bluetooth on and connect to something. Grayed-out toggles indicate a board-level fault.
- Cellular. Check you get signal and can use mobile data.
- Heat. After 10 minutes of use, the phone shouldn’t be unusually hot while idle.
On most Samsung phones you can open a hardware test menu by dialing *#0*#, and the Samsung Members app has a full diagnostics section. Our guide to Android diagnostic codes explains what each test means.
Step 4: Read the software warnings
Phones increasingly detect moisture themselves:
- iPhone: “Liquid Detected in Lightning Connector” (or USB-C connector) alerts appear when the port is wet. One alert after a rainy day is normal; an alert that keeps appearing on a dry phone points to corrosion in the port.
- Samsung: a “Moisture detected” warning blocks wired charging until the port is dry. If it appears with a completely dry port, the port may be corroded.
- Battery: on iPhone, check Settings › Battery › Battery Health. A sudden drop or a “Service” message on a young battery can follow liquid exposure. Read our battery and parts guide for how to read these screens.
Step 5: Check the records
A phone’s history can reveal what its owner won’t. For iPhones, the Apple full GSX report includes repair case history and replacement details — if the device was taken to Apple for liquid-related issues or swapped under service, it often shows there. A warranty check tells you whether coverage is still active, which matters if you plan to claim on it (liquid damage is typically excluded from standard warranties).
For Samsung, a Samsung Info report confirms the model, warranty and region. And on any phone, an All-in-one Basic Info check confirms the model matches what the seller claims — water-damaged phones are frequently rebuilt with mismatched parts. Finish with a GSMA blacklist check; a damaged phone that was insured may have been claimed and reported.
Making the decision
| What you find | What it likely means | Advice |
|---|---|---|
| LCI white, no corrosion, all tests pass | No sign of liquid damage | Proceed with normal checks |
| LCI red, all tests pass | Liquid contact, damage may not have started | Only buy at a big discount, no warranty expected |
| Corrosion in port, charging intermittent | Active corrosion | Walk away unless you repair boards |
| Fog in camera, screen blotches | Moisture inside the body | Walk away |
| Face ID / Wi-Fi unavailable | Board-level or module damage | Walk away |
Our check before buying page brings the rest of the inspection together. When you’re ready, run the records checks on the IMEI:
Frequently asked questions
Where is the water damage indicator on an iPhone?
On iPhones with a SIM tray, it is inside the SIM tray slot. Remove the tray and shine a flashlight inside. White or silver is normal; red or pink means liquid contact.
Can a water-damaged phone work fine at first?
Yes. Corrosion often develops over days or weeks, so a phone can pass a quick test and still fail later. That is why indicators and port inspection matter.
Does Apple warranty cover water damage?
Liquid damage is generally not covered by Apple’s standard limited warranty, even on water-resistant iPhones. AppleCare plans may cover accidental damage with a service fee.
How do I check a US eSIM-only iPhone for water damage?
Its indicator is internal, so rely on corrosion checks at the port, functional tests, Liquid Detected alerts and the repair history in a GSX report.
Will putting a wet phone in rice fix it?
Rice does not remove corrosion and can leave dust in the ports. Power the phone off, let it dry in open air and have it inspected if it shows symptoms.
