You walk into your room and find a puddle of water under the indoor AC unit. Or you notice water dripping from the front panel onto your floor, furniture, or worse — your wall. This is one of the most common AC complaints in Kolkata, and it tends to get worse during the monsoon and peak summer months.
The good news: AC water leakage inside the room is almost always fixable — and in many cases, you can solve it yourself in under 10 minutes. This guide covers all the main causes and exactly what to do about each one.
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Unique Aircon — a certified AC service team based in Jadavpur, serving South and Central Kolkata for 9+ years. If your AC is leaking water and you need same-day help,
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+91 83469 04100.
Is AC Water Leakage Dangerous?
Water leaking from an AC indoor unit is not immediately dangerous to you — but it should not be ignored. Left unattended, it can:
⚠
Damage walls, ceilings, and furniture — especially in Kolkata flats where water seeps into plaster quickly
⚠
Cause mould and mildew growth inside the indoor unit — which then circulates into your room air
⚠
Short-circuit electrical components if water reaches the wiring inside the unit
⚠
Signal a bigger problem like low refrigerant gas — which if ignored leads to compressor failure costing ₹6,000–₹18,000
So if your AC is dripping water inside the room — address it today, not next week.
6 Reasons Your AC is Leaking Water Inside the Room
1
Blocked or Clogged Drain Pipe (Most Common)
Your AC produces condensation water as it cools — this is completely normal. This water is supposed to drain out through a pipe that runs from the indoor unit to an outside drain point. When this pipe gets blocked by algae, dust, insects, or debris — the water has nowhere to go and overflows into the room.
In Kolkata's humid climate, drain pipes block much faster than in drier cities. During monsoon season (June–September), algae growth inside the drain pipe can completely block it in just 4–6 weeks.
How to identify it: Water drips steadily from the bottom of the indoor unit even when the AC is running normally and cooling well. The drip is consistent, not occasional.
DIY fix: Locate the drain pipe outlet (usually a small PVC pipe coming out of the wall below the indoor unit outside). Use a wet-dry vacuum or blow compressed air into the pipe from the outside end to clear the blockage. Alternatively, pour a cup of diluted bleach into the drain pan inside the unit to kill algae. If this does not work within 24 hours, call a technician to clear it with a drain snake.
2
Frozen Evaporator Coil Melting
When refrigerant gas is low or airflow is restricted (due to a dirty filter), the evaporator coil inside your AC gets too cold and freezes over. When the AC is turned off — or when the compressor cycles off — the ice melts rapidly and releases far more water than the drain pan can handle, causing a sudden flood of water inside the room.
This is the most serious cause because it signals an underlying problem — low gas or dirty filter — that will damage your compressor if not fixed.
How to identify it: You notice frost or ice on the copper pipes near the indoor unit. Water leaks heavily when AC is switched off. AC is also not cooling well.
What to do: Switch the AC off immediately and let it thaw completely (2–3 hours). Check and clean the air filter. If the problem returns after cleaning, your gas level is likely low — call a technician to check gas pressure. Read our
AC gas charging cost guide to understand what a refill will cost.
3
Dirty or Clogged Air Filter
A severely blocked air filter restricts warm air flowing over the evaporator coil. Without enough warm air passing over it, the coil gets too cold and freezes — which as described above leads to water overflow when it melts. A dirty filter is one of the top two causes of AC water leakage in Kolkata.
How to identify it: Open the front panel of the indoor unit. If the filter is visibly grey, clogged with dust, or has not been cleaned in 4+ weeks during summer — this is very likely the cause.
DIY fix: Remove the filter, rinse it under running water, let it dry completely, and reinsert. Run the AC again. If water leakage stops, the dirty filter was the cause. Clean filters every 3–4 weeks during Kolkata summer — more frequently in rooms near roads or construction sites.
4
Incorrectly Tilted Indoor Unit
The indoor unit must be installed with a very slight tilt — the back of the unit should be marginally lower than the front, so condensation water naturally flows toward the drain pipe. If the unit is level or tilted the wrong way, water pools in the drain pan and overflows into the room instead of draining out.
This is common in Kolkata homes where AC units were installed by non-certified technicians, or where the wall bracket has shifted over time due to vibration or wall settling.
How to identify it: Water drips from the front or sides of the indoor unit rather than the back drain. The problem is consistent and has been present since installation or after the unit was moved.
What to do: This requires a technician to re-level the unit on its bracket. Do not attempt to adjust the bracket yourself — the indoor unit is heavy and a fall could cause serious damage or injury.
5
Cracked or Disconnected Drain Pan
The drain pan sits beneath the evaporator coil and collects condensation before routing it to the drain pipe. In older AC units — typically 7 years or more — the drain pan can crack due to age, physical stress, or freezing and thawing cycles. A cracked pan leaks directly into the room regardless of whether the drain pipe is clear.
How to identify it: Leaking persists even after the drain pipe has been cleared and filter cleaned. The AC is an older model (7+ years). A technician can visually inspect the pan by opening the unit.
What to do: Drain pan replacement in Kolkata costs approximately ₹800–₹2,500 depending on the brand and model. For very old ACs, consider whether a full service or replacement makes better long-term sense.
6
Monsoon Humidity Overload
During Kolkata's monsoon (June–September), outdoor humidity regularly crosses 90%. When a room is very humid and the AC is set very cold, the amount of condensation produced can temporarily exceed the drain system's capacity — especially if the drain pipe is partially slow rather than fully blocked.
This is more of a seasonal issue and often resolves by slightly raising the set temperature (from 18°C to 22°C) or keeping the AC in Dry mode during the most humid days.
What to do: Set the AC to 23–24°C instead of 18°C during peak monsoon humidity. Use Dry mode on very humid days — it removes moisture from the air without aggressive cooling. Also make sure your drain pipe is fully clear before monsoon begins each year.
Quick Reference — Cause, Fix & Cost
| Cause |
Fix |
Cost (Kolkata) |
DIY? |
| Blocked drain pipe |
Flush or vacuum the drain pipe |
Free – ₹500 |
Partly |
| Frozen coil (low gas) |
Gas refill + leak repair |
₹1,500 – ₹4,500 |
No |
| Dirty air filter |
Wash and reinstall filter |
Free |
Yes |
| Incorrect unit tilt |
Re-level the indoor unit bracket |
₹400 – ₹800 |
No |
| Cracked drain pan |
Replace the drain pan |
₹800 – ₹2,500 |
No |
| Monsoon humidity overload |
Use Dry mode, raise set temperature |
Free |
Yes |
⚠ Important: If you are not sure of the cause, do not keep running the AC. Switch it off and call a technician. Running an AC with a frozen coil or low gas can permanently damage the compressor.
How to Prevent AC Water Leakage in Kolkata
Most water leakage issues are 100% preventable with a simple annual routine:
✓
Get your AC serviced every year before summer (February–March). A proper service includes drain pipe flushing, coil cleaning, filter wash, and gas pressure check — all the things that prevent leakage.
✓
Flush the drain pipe with diluted bleach once at the start of monsoon. This kills algae before it can grow into a blockage. Pour half a cup of diluted bleach into the drain pan — it will flow through the pipe and clear early-stage growth.
✓
Clean air filters every 3–4 weeks during summer. A clean filter is the single easiest thing you can do to prevent both water leakage and poor cooling.
✓
Never ignore the first sign of dripping. A small drip today becomes a wall-staining overflow in two weeks. The earlier you address it, the cheaper the fix.
Frequently Asked Questions
Q
Is some water dripping from AC normal?
A small amount of water dripping from the outdoor unit is completely normal — that is the condensate draining outside as it should. Water dripping from the indoor unit inside your room is not normal and always indicates one of the causes listed above.
Q
Can I use the AC while it is leaking water?
We recommend switching it off until the cause is identified. If water reaches the electrical components inside the unit, it can cause a short circuit. If the cause is a frozen coil due to low gas, continuing to run the AC will damage the compressor.
Q
My AC leaks only during monsoon — is that normal?
Not exactly normal, but very common in Kolkata. It usually means the drain pipe has partial blockage that the normal condensation volume can manage — but the extra moisture during monsoon pushes it over the limit. Getting the drain pipe flushed before monsoon each year will prevent this completely.
Q
How much does it cost to fix AC water leakage in Kolkata?
If the cause is a blocked drain pipe or dirty filter — as little as ₹0 to ₹500 (or free if you do it yourself). If it is a frozen coil due to low gas, expect ₹1,500–₹4,500 for gas refilling. A cracked drain pan costs ₹800–₹2,500 to replace. At Unique Aircon, we diagnose first and quote transparently before any work begins.
AC Leaking Water in Kolkata? We'll Fix It Today.
Same-day diagnosis and repair across South & Central Kolkata. Transparent pricing, no hidden charges.
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Last updated: June 2026 · Written by the Unique Aircon technical team, Kolkata
