Maintenance Guide
Water dripping from an AC indoor unit is one of the most common complaints Air Control receives across Delhi, Gurgaon, Noida, and Faridabad — particularly during the pre-monsoon and monsoon seasons when humidity is high. The good news is that the cause is usually simple and fixable quickly. The concern is what the water damage can do to your walls, ceilings, and furniture if left unattended. This guide explains every cause of AC water leakage and what you can do about each one.
When warm, humid room air passes over the cold evaporator coil inside the indoor unit, moisture in the air condenses on the coil — exactly like water droplets forming on a cold glass. This condensed water is completely normal and drips into a drain tray beneath the coil, then flows out through a drain pipe to the outside. A well-maintained AC handles this silently and invisibly. When any part of this drainage chain fails, water backs up and leaks into the room.
This is the cause in approximately 70% of all AC water leak cases that Air Control diagnoses across Delhi NCR. Over months of use, algae, mould, dust, and debris accumulate inside the narrow (typically 1.5–2 cm diameter) drain pipe and restrict or completely block the flow of water. The drain tray fills up and overflows into the room. During Delhi's monsoon, when the volume of condensation is highest, even a partially blocked pipe quickly overflows.
Solution: The drain pipe must be cleared with a wire, wet-and-dry vacuum, or pressurised water flush. This is a standard part of Air Control's AC service visit.
When the air filter is heavily blocked, airflow over the evaporator coil drops sharply. The coil becomes excessively cold and the moisture on it freezes into ice rather than dripping into the drain tray. When the AC cycles off or the ice accumulates enough, it melts — producing a sudden rush of water that overwhelms the drain tray. Clean your filter every 2–3 weeks during peak summer in Delhi.
Low refrigerant causes the evaporator coil to operate at abnormally low temperatures, causing ice to form on the coil and copper pipe. When this ice melts (often when the compressor cycles off), large amounts of water drip from the indoor unit. The water leak here is a secondary symptom of a primary gas problem — fixing only the drainage without addressing the refrigerant issue will not solve the problem.
The indoor unit must be mounted with a very slight backward tilt (toward the wall) so that condensation flows naturally toward the drain outlet. If installed level or tilted the wrong way, water pools at the front of the unit and drips down the wall rather than flowing to the drain tray. This is an installation error that Air Control sees frequently when customers switch from unqualified installers to us. We have corrected improper installations across Gurgaon DLF and Noida sectors.
Older ACs develop hairline cracks in the plastic drain tray through thermal cycling and age. Water leaks through the crack even when the drain pipe is clear. In some cases, the tray's drainage hole becomes blocked with sludge — the tray itself needs cleaning or replacement.
In Delhi's July–August monsoon, outdoor humidity can exceed 90%. When doors and windows are open while the AC runs, very humid air enters constantly, causing the evaporator coil to produce condensation faster than even a clear drain pipe can handle in some older or undersized installations. The solution is to keep doors and windows closed when the AC is running during high-humidity conditions.
Check the air filter. Remove it (usually accessible by lifting the front panel), rinse under a tap, and let it dry completely before reinstalling. If the leaking stops within an hour of reinstalling a clean filter, filter blockage was the cause.
Check the drain pipe outlet. Find where the drain pipe exits the building (usually through a small hole in the wall behind the indoor unit). Pour a cup of water into the drain tray — it should flow out the pipe within 30 seconds. If it backs up, the pipe is blocked.
Try to clear the drain. Insert a thin flexible wire (or use a wet-and-dry vacuum at the outlet end) to dislodge the blockage. Flush with water. If the blockage does not clear, call Air Control — we carry equipment for thorough drain cleaning.
Check for ice on the copper pipe. If you see ice or frost, switch the AC off for 2–3 hours to let it melt, then call Air Control. The ice indicates low refrigerant or severe airflow restriction — do not restart until this is diagnosed.
Call Air Control immediately if: the leak is heavy and continuous, ice is present on the unit, the leak occurs even after you have cleaned the filter, or the drain pipe appears clear but water still leaks. Air Control has resolved 400+ water leak cases across South Delhi, Central Delhi, Gurgaon, and Noida. Our technicians arrive with drain cleaning tools, pressure washers, and diagnostic equipment to identify the true root cause.
The most common cause is a blocked condensate drain pipe, which prevents condensation from draining outside. Other causes include a dirty air filter, low refrigerant causing ice formation, an incorrectly angled indoor unit, or a cracked drain tray. Most cases are resolved by clearing the drain pipe.
If the leak is due to a blocked drain, running the AC briefly is not immediately harmful to the unit, but the water can damage walls and ceilings. If ice is visible on the coil alongside the leak, switch the AC off immediately — this indicates a more serious problem requiring professional attention.
Yes, if you can safely access the drain pipe outlet. You can try clearing it with a thin wire or by blowing through it. For complete cleaning of the drain tray and pipe using pressurised water, a technician visit is recommended — this is included in Air Control's standard service.
During Delhi's monsoon, outdoor humidity is very high. The AC's evaporator coil condenses far more moisture from the humid indoor air, producing more water than usual. If the drain pipe is even slightly clogged, this higher volume of water overflows the tray. Monsoon is the peak season for AC water leak calls in Delhi NCR.
Drain pipe cleaning is typically included in a standard AC service (₹400–₹800 for the service). If the drain tray is cracked and needs replacement, that adds ₹600–₹1,500. If low refrigerant is causing icing and secondary water leakage, gas top-up adds ₹1,500–₹2,500. Air Control provides a full quote before any work begins.
Air Control · Sant Nagar, East of Kailash, New Delhi · +91 93122 64832 · ajay@aircontrols.in