Expert guide to preventing and handling condensation and frozen pipe problems that frequently occur in rental apartments during winter. Clear explanations of how to request repairs from your management company and how to understand cost responsibility.
Reviewed by: Nobuyuki MoriPresident, M-Assets Co., Ltd. / Licensed Real Estate Transaction Specialist (Miyagi #018212)
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When winter arrives, two major problems frequently occur in rental apartments. One is condensation, and the other is frozen pipes. Many residents suffer from these issues without knowing how to handle them, even though both can lead to serious damage if left unaddressed.
Condensation is the phenomenon of water droplets forming on window glass and window frames. If left unchecked, it leads to mold growth. Once mold spreads, it can cause health problems and may also affect your move-out restoration costs. On the other hand, frozen pipes occur when water inside the water pipes freezes and stops working. In the worst case, the frozen water expands, causing the pipes to burst and leading to serious water leaks.
This article explains in detail winter trouble prevention for rental apartments, from the causes of these problems to prevention methods, how to handle them if they occur, and how to request repairs from your management company.
Condensation occurs when warm, humid air from inside your apartment comes into contact with cold window glass or walls, causing the water vapor in the air to turn into water droplets. Especially in winter, because of the large temperature difference between inside and outside, condensation is more likely to form.
Condensation is likely to form in the following places:
1. Regular Ventilation Open windows every 1-2 hours to ventilate and reduce indoor humidity. Keep ventilation fans running continuously as a basic rule. Be especially diligent about ventilation during and after cooking and bathing, when moisture increases.
2. Humidity Control It is ideal to keep indoor humidity at 40–60%. If using a humidifier, avoid over-humidifying and manage it with a humidity meter. Note that houseplants also release moisture, so be careful not to have too many.
3. Use Condensation-Prevention Products Applying condensation-prevention film (sold at home improvement stores) to window glass raises the glass surface temperature and reduces condensation. You can also apply condensation-absorbing tape along the window sill to prevent moisture from spreading.
4. Rearrange Your Furniture When furniture is placed tightly against an exterior wall, air cannot circulate behind it, making condensation more likely. Position furniture at least 5 cm away from exterior walls to allow proper air circulation.
5. Choose the Right Heating Appliance Oil heaters and gas stoves generate large amounts of water vapor during combustion, promoting condensation. Choosing heating appliances that don't produce water vapor—such as air conditioners or oil heaters—makes it easier to prevent condensation.
If you leave condensation uncleaned, mold will develop on walls and around window frames. Mold can cause allergies and asthma, and may also damage wallpaper and wood.
When you move out, normal wear and tear from regular use is the landlord's responsibility. However, damage or stains caused by neglected mold may be considered the tenant's fault, and you could be charged for restoration to original condition.
When you notice condensation, the basic step is to immediately wipe away the moisture with a dry towel or a specialized condensation wiper. If mold has developed, treat it early with commercially available mold remover.
If mold has already spread over a large area, it may be difficult to handle on your own. In that case, consult with your management company about hiring a professional cleaning service.
However, if mold was already present when you moved in, or if it developed due to poor insulation in the building itself, you can request that the landlord handle it as their responsibility.
When temperatures drop below −4℃, the risk of frozen pipes increases, especially for uninsulated exposed water pipes and pipes near exterior walls. Pay special attention in these situations:
Drain the Water When you'll be away for an extended period, draining the water—closing the main water shut-off valve and emptying the pipes—is the most reliable way to prevent freezing. The method varies by property, so it's important to get an explanation from your management company when you move in.
The basic steps for draining water are as follows:
Let a Small Amount of Water Run Continuously For short trips or overnight, you can sometimes prevent freezing by letting a very thin trickle of water (about the thickness of a pencil lead) run continuously from a faucet. However, be aware that this increases your water bill and its effectiveness is limited.
Use a Freeze-Prevention Heater Some properties have electric heaters wrapped around the water pipes to prevent freezing. Keeping the power on during winter prevents freezing.
If pipes freeze, the first thing to do is wait for them to thaw naturally. Never pour hot water on frozen pipes, as this can damage them.
If you need to act quickly, you can soak a towel in lukewarm water (around 30–40℃) and apply it to the frozen section to gradually thaw it, or use a commercial hair dryer to warm it.
If that doesn't work, contact your management company immediately for guidance. If a pipe bursts, close the main water shut-off valve to stop the water flow, and contact your management company or an emergency repair service right away.
Under the Land and Building Lease Act and civil law, the landlord (property owner or management company) is generally responsible for repairs in a rental property. If equipment malfunctions or damage occurs from structural problems despite proper use by the tenant, the tenant can request repairs from the landlord.
On the other hand, if a problem occurs due to the tenant's carelessness or lack of maintenance (for example, failing to drain water and causing pipes to freeze and burst, or neglecting ventilation and causing mold to develop and spread), the tenant may be responsible for costs.
1. Document the Situation When a problem occurs, first document it with photos or video. Taking clear photos with the date and time and showing the extent of damage helps prevent disputes later.
2. Contact Your Management Company Promptly After documenting, contact your management company or landlord immediately. It's important to report not just verbally, but through email, LINE, or other methods that create a written record. Be specific about when, where, and what happened.
3. Confirm the Repair Request and Contractor Arrangement If the management company arranges a contractor, confirm the repair details and cost responsibility in advance. If costs will be incurred, it's important to confirm who will pay in writing or through a documented communication.
4. You Can Take Action in an Emergency In emergencies, such as a burst pipe flooding the apartment, you may take immediate action (such as closing the main shut-off valve) without waiting for the management company's instructions. Report the situation to the management company promptly afterward. Note that you may be able to claim reimbursement for emergency response costs.
| Situation | Cost Responsibility |
|---|---|
| Equipment failure due to normal aging of the building | Landlord's responsibility |
| Freezing or bursting due to tenant fault (neglecting to drain water, etc.) | Possibly tenant's responsibility |
| Mold development or spread due to lack of ventilation | Possibly tenant's responsibility |
| Minor staining from condensation within normal use | Landlord's responsibility |
| Problems that existed when you moved in | Landlord's responsibility |
Winter condensation and frozen pipe problems in rental apartments can be greatly reduced through proper knowledge and daily prevention practices.
Before moving in, it's an important step to confirm winter precautions (such as how to drain water) with your management company. Don't hesitate to ask your management company if you have any questions. Refer to this article for a comfortable and secure winter rental living experience.
Condensation that forms on windows and walls during winter can lead to mold if left unchecked, harming both your health and the building. This guide thoroughly explains how condensation occurs, along with prevention and removal methods you can practice even in rental apartments.
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