Moisture behind a dive computer's screen can point to a damaged seal, a cracked case or lens, a battery problem or damp air trapped inside, but you cannot tell which from the outside. The next step is to stop relying on the unit and contact the maker or an authorized service center, not to dry it out or open it yourself. Document what you see, keep your receipt and check the warranty terms, because accidental damage is often excluded.
What moisture behind the screen can mean
Dive computers are sealed, and the screen, case and any user-serviceable battery compartment are all places where a seal can fail. When you see fog, droplets or a film behind the glass, several things might be going on, and a gear guide cannot tell you which. Possibilities include a damaged seal or O-ring, a crack or chip in the case or lens, damage to the battery compartment, or humid air that was trapped when the case was last closed.
The honest answer is that the maker or a service center has to look. Fog that clears might still point to a seal problem, and a small amount of water can damage electronics even if the screen still works. Treat any moisture as a reason to have the unit checked, not as a cosmetic quirk. Our dive computer maintenance and battery care guide covers routine care for the compartment and case.
What to do first
- Stop relying on it. A computer with suspected moisture should not be trusted until the maker or an authorized service center has examined it. Ask your instructor or training agency how to handle diving without it.
- Do not open it or dry it with heat. Home fixes can make a problem worse and can affect your warranty. Only follow drying or battery instructions that appear in the maker's manual.
- Photograph the problem. Take clear pictures of the screen, case and battery area, and note the date and what you were doing when you noticed it.
- Collect your paperwork. Find the receipt, serial number and the warranty text, along with any service records.
- Contact the maker or seller. Follow their process for a service or warranty claim.
On a trip this may be an awkward moment. Our guide to what to do if a dive computer fails on a trip looks at the practical side, including the value of a backup. Decisions about continuing to dive without a computer are for your instructor, dive operator and training agency.
Warranty and service: how the routes work
Who pays depends on the cause, and the cause is something the maker decides. Shearwater's warranty page, for example, says its two-year coverage applies to the unit and not the original buyer, that defective covered products are repaired or replaced at its discretion, and that unauthorized repairs, accidental damage and negligence are not covered. The same page says damage from battery leaks in computers with user-changeable batteries is not covered, and warns that leaving alkaline batteries in for long periods raises the risk. Other makers' terms differ, so read yours.
That has a practical implication. If a seal failed through a defect, the warranty may respond. If the computer was dropped or the case was cracked, the claim may be treated as accidental damage. Opening the case yourself, or having someone unauthorized do it, can be a reason a claim is refused, depending on the warranty wording. In the United States, the FTC's guide to warranty law says a written warranty on a consumer product costing more than $15 must be available before you buy it, so you can ask the seller or maker for the text. Our dive gear warranty guide goes through the typical terms.
Dive computer hard case
Best for: Protecting a computer from knocks between dives
Accidental damage is commonly excluded from warranties, so a case that suits your computer's size is worth considering. Check how it fits with the strap attached.
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Service routes compared
| Route | What it can do | Keep in mind |
|---|---|---|
| Maker or authorized service center | Inspect the unit and say whether the warranty applies | Follow the maker's process; unauthorized repairs may not be covered |
| Seller or dive shop | May handle a return or pass the unit to the maker | Read the seller's return window and any shipping terms |
| Third-party repairer | May offer a repair outside the maker's network | Check with the maker first, because coverage may be affected |
| You at home | Photograph, document and contact the right people | Do not open or heat the unit |
Servicing also matters before a problem appears. DAN's gear care guidance says to rinse and dry the computer after diving, store it somewhere dry, cool and ventilated, and have it serviced every one to two years or as the manufacturer recommends. That is care advice, not a cure, and it does not replace the maker's own manual.
Storing a computer dry
Moisture can also come from how a computer is stored. Rinsing, drying and keeping the unit in a dry, ventilated place between trips, as DAN suggests, avoids creating damp conditions. Avoid sealing a wet computer in a closed case or pouch. If you use silica gel packs in your gear case, check the packs are meant for that use and that they do not touch the screen or straps. Our battery care and storage guide and off-season storage guide cover the wider routine.
If you are comparing computers with user-changeable batteries against sealed units, our rechargeable versus replaceable battery comparison explains the trade-offs. Neither type is immune to moisture problems.
Silica gel packs for gear cases
Best for: Keeping a stored case dry between trips
Choose packs sold for use with electronics or camera gear, and keep them away from the screen. Replace or recharge them as the maker of the packs advises.
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When it may be time to replace it
A repair is not always worth it. If the unit is old, out of warranty or has been serviced before, ask the maker for a quote and compare it with the cost of a replacement. Our guide to when to replace a dive computer looks at the decision. If you do buy again, ask about the warranty and service network first.
A second computer is also worth thinking about for trips, because a problem with one does not leave you without the other. Our backup computer guide covers when that makes sense. Your instructor and training agency can advise on how a backup fits the way you dive.
Backup dive computer
Best for: Divers who want a second unit for trips
Compare the warranty terms, charging or battery type and display, and read the manual before buying. Used units can suit this role if the seller offers returns.
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Frequently asked questions
Is fogging inside a dive computer normal?
Do not assume so. Fogging or droplets behind the screen can point to a seal or case problem, so have the maker or an authorized service center examine it.
Can I dry a wet dive computer at home?
Only follow drying instructions in the maker's manual. Heat and home repairs can make the problem worse and can affect your warranty.
Will the warranty cover moisture damage?
It depends on the cause and the wording. Shearwater's warranty excludes accidental damage, negligence and unauthorized repairs, and other makers differ. Read your warranty and contact the maker.
Should I keep diving with the computer?
Do not rely on a computer you suspect has moisture inside until the maker or a service center has examined it. Ask your instructor or training agency about diving without it.
What should I send with a service claim?
Photographs of the problem, the date you noticed it, the receipt, the serial number and any service records. Follow the maker's instructions for sending the unit.