Are Air Conditioners Supposed To Leak Water? Why AC Leaking Water Is Normal

Air Conditioning

We love our air conditioners. They cool our home, help us sleep at night and protect our homes from hot humid environments. But that doesn’t mean they don’t come with the occasional concerns. Like when you hear dripping water from the AC. Are air conditioners supposed to leak water?

Yes, air conditioners are supposed to leak water from an attached condensate drain line during normal operation of your hvac system. If everything is operating properly, it’s possible to hear the water dripping. But if you see the water dripping from a ceiling or pooling in an area around the hvac system than you have a problem.

DP are air conditioners supposed to leak water

Why Is My AC Leaking Water?

Remember how humid your house was before you turned on your air conditioner. That humidity is the water your air conditioner is removing from your home. It does this by condensation.

Our air is full of water, and not just in the form of rain. Water vapor present even when you can’t see it. Condensation is what happens when this invisible vapor becomes a visible liquid. 

You see condensation around you all the time. It’s the reason why your glasses fog up when you go from a cold room to the outdoors on a hot, humid day. Or the reason water drips off the outside of your glass of ice water.

Within AC system there is an evaporator coil with an attached pan to collect water. This coil is a group of copper or aluminum tubes coiled back and forth with aluminum fins or plates across them and is usually installed inside the ductwork of your home. 

As the relatively warm and humid air within your home passes over the cold evaporator coil, moisture collects (just like on a cold glass) and is directed into the attached drain pan and drain line.

As long as the water is following the drain line to the outside or to a drain inside the home the AC system is operating normally. But if you see leaking water inside from a ceiling, water coming out of a drain line pipe that’s normally dry or water around the indoor hvac equipment there is a problem. What should you do then?

When the AC Unit Leaking Water Is a Problem

I understand that leaking air conditioners are a problem you don’t need. But when you see leaking water, there are some things you can do. An AC unit leaking water basically has three common causes. Let’s talk about them and possible remedies.

Clogged Condensate Drain Line

The air conditioner’s drain line is most commonly a white 3/4″ PVC line connected to the drain pan. If your air conditioner equipment is in an attic, you’ve probably never noticed. But if your air conditioning unit is in a closet near the living area or in a basement, this drain line can be easily seen.

Dirt and debris can find its way through your ductwork and into your AC system. One area of accumulation of this dirt is the evaporator coil. Once there, the water easily pulls some of the dirt down the coil and into the drain system where it can accumulate. 

If the accumulation of dirt is bad enough, you’ll see the AC leaking water outside of the attached piping.

This is another good reason to have a high quality air cleaner installed on your hvac system.

Another potential problem is areas where there is standing water in the AC drain line. This could be in a trap, just like the ones below your sink and usually required by code, or in part of piping that isn’t pitched properly.

In these cases, organisms can grow and accumulate to the point of blocking water flow.

If you find yourself in this situation, you have two choices. you can disconnect the piping near the indoor air conditioner equipment and clear the line with either compressed air or water. Water, while not always an option, is preferred because it ensures that all the dirt will be cleared. Air can sometimes just poke a hole in the clog and you’ll be seeing leaking water again in no time.

Your other choice is of course to call a quality hvac company to care for the problem.

Failed Condensate Pump

In some cases, a gravity drain isn’t the best choice for your air conditioner condensation. In those cases a small condensate removal pump is installed. The drain is then tied to the pump which is located near the indoor hvac equipment. When the water in the condensate pump reaches a certain level the pump is activated and the water is pushed to the outdoors or to a drain.

If the pump fails to operate you’ll see leaking water around the hvac equipment. Or, if the pump has a safety switch that senses a problem and the installing hvac company tied the safety switch into the AC system, your air conditioner will fail to operate. This is a nice feature to prevent leaking water to damage a ceiling or finished floor.

Once again you have two choices if this pump fails to operate. You can remove the pump and clean the interior in case any dirt or debris is jamming the mechanisms. Or you can call your local hvac company to diagnose the issue and maybe install a new pump.

Dripping Water from a Frozen Evaporator Coil

If you see water leaking from around the indoor air conditioner unit AND there is little to no air coming from your vents you most likely have a frozen coil.

This is a condition where ice forms on the coils inside of the AC system. Once this ice begins to melt it bypasses the drain pan and leaks you’ll see the evidence of a water leak.

There are multiple causes for this but the three most common are low refrigerant, a very dirty filter and a failed blower motor or control.

The only DIY repair of those three is the air filter. If you see your air filter is the cause, replace or clean it and shut down your AC system for 12-24 hours. This will give the AC time for the ice to melt.

Is It Safe To Use The HVAC System When You See Water Leaking

It is NOT safe to use the air conditioning system when you see water leaking. The best thing to do if you see your AC leaking is to shut down the system. Air conditioner leaks can do quite a bit of damage to ceilings, floors and internal AC components.


It’s so easy to get used to your air conditioning system leaking, that you don’t even realize whether it’s normal or not. But it’s when you see water leaking on the outside of your AC that you realize a problem.

When in doubt the best advice I can give you is to call a professional. The pros are there to help you fix the problem and they can determine the best way to minimize the damage. And often it’s as simple as giving the AC system a good tune up.

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