How Much Water Is Normal to Have in an AC Drip Pan

Have you ever opened your air conditioning unit and found standing water in the drain pan? 

An inch of water in your air conditioner’s drain pan is normal and okay. After all, it’s supposed to collect the condensation that comes off of the evaporator coil. However, if the water is not draining out of the pan and you have an excess of stagnant water, you likely have a clog in the drain line that needs to be addressed to avoid any further problems.

In this article I’ll go over all the things that could possibly go wrong with your drain pan and its drainage system, and how you can fix them before enlisting the help of a professional. Hopefully this will save you a bit of money and avoid bigger problems down the road. 

Why Does Your Air Conditioner Drip Water?

Water dripping out of your AC is entirely normal. In fact, it’s a sign that everything is running properly. To better understand why your air conditioner drips water, let me briefly explain how the air conditioner works.

An air conditioner pulls the warm air from inside your house and passes it over the evaporator coils which hold liquid refrigerant. When the liquid refrigerant turns into gas, heat and moisture from the warm air are absorbed, thus cooling the air. The fan then sends that cool air back into your home.

Condensation occurs when warm moist air moves over cold objects. So, as the heat and moisture are absorbed during the cooling process, condensation is created in your AC unit. 

That condensation drips down into the drain pan, which then flows out of the unit through the drain pipe, also known as the condensate line, which carries the water to a safe drain spot outside.

How Much Water Should Drip Out of Your AC?

You should always keep an eye on how much water is coming out of the condensate line because too much or not enough water coming out could be a sign that something is wrong and needs attention.

A typical AC system will drain approximately 1 gallon of water every hour that it is running, but that can vary depending on how much moisture is in the surrounding air.

That can fluctuate depending on the level of humidity where you live, or even how much you cook on any given day since cooking will also create more steam and moisture inside your house to be drawn out by the cooling process of your air conditioner.

I recommend getting an idea of what a normal flow of water draining looks like for your particular AC when your system is clean and running fresh, and then monitoring it for any changes. 

What If It’s Not Draining Enough Water?

If not enough water is coming out of the condensate line, it means one of two things; Either your AC is not producing condensation or you have a clog somewhere in the condensate line.

As I said before, condensation is a normal byproduct of the cooling process, so if your AC is not producing it, it probably means it’s not cooling properly either. If that’s the case, you’ll want to find out which part of your AC is not working and get the issue fixed. 

On the other hand, if your unit is producing condensation it needs to be able to properly drain out of the drain pan. The wet environment on the inside of your condensate line is an ideal place for bacteria and mold to grow and other debris to collect. Those things can build up over time, creating clogs.  

A clogged drain pipe can lead to an overflowing drain pan because the water will back up into the drain pan rather than flow down the pipe and out of the house which can cause serious water damage inside your house or even to the AC unit itself.

Problems with Your Drip Pan and How to Fix Them

While water dripping out of your AC’s condensate line is totally normal and a sign that everything is functioning properly, any kind of water dripping under your AC is not normal and can mean that there is a problem with the drain pan or its drainage system.

An overflowing drain pan can not only cause water damage to the space underneath your air conditioner, but it can also damage parts of your air conditioner. Think of how many electrical parts are in the unit! 

The first thing you want to do if you notice that your drain pan is full of water or your air conditioner is leaking is shut off the power to your unit. You can do that by flipping the breaker in the main breaker box. Then try to find out what is causing the problem.

Let’s take a look at a couple of things that can go wrong with your drain pan and how you can fix them before calling your local HVAC technician out. 

Clogged condensate line

As I mentioned above, a clogged condensate line can cause water to back up in the drain pipe and cause it to overflow in your unit. To avoid this, I recommend cleaning out your condensate line regularly. 

If you suspect a clog, first try to get it out using a wet/dry vacuum. Connect the vacuum to the outside end of the pipe, stuff a small hand towel around the edge to fill in any gaps and get a tight seal on it, and turn the vacuum cleaner on.

If that doesn’t work or if you suspect there is still some buildup in the line, you can use a long wire brush cleaner to thoroughly clean the pipe. It may be hard to get into the pipe through the AC unit, so what I usually end up doing is cutting a piece of the pipe not far down the line from the AC unit which, in my experience, is where most clogs happen. 

You can put the pipe back together afterward using a small piece of rubber piping to act as a coupling. This will also allow you to easily access the inside of the pipe again to keep it clean. 

But before you put it back together, it’s not a bad idea to pour a vinegar solution through the pipe as well.

This will help clean the pipe and kill any mold in the pipe and prevent it from coming back. To do this, open your AC unit and pour a few cups of white vinegar solution into the drain pipe. Make sure you have a bucket on the cut end of the pipe to catch it. Follow up with a bit of warm water to flush out the drain pan and pipe. 

You have a rusted drain pan

If your drain pan is rusted, which can happen over time, you’ll want to replace it right away. If you don’t, the condensation that collects in it will leak out of the bottom of your air conditioner rather than sending it out through the drain pipe to drain outside in a safe location. 

If you are looking for a quality replacement pan, you’ll want to look for a pan that’s made of stainless steel. Stainless steel is durable and easy to clean. Plus, it doesn’t rust easily.

The coil is frozen

Frozen coils could be caused by a number of different things. One very common culprit is a dirty air filter or coil. When you have a dirty filter or coil, the airflow to the unit is restricted which causes the coil to become too cold and freeze. 

Low refrigerant levels and even a clogged condensate line can also cause the coil to freeze. But no matter the cause, a frozen evaporator coil is never a good thing. When the ice thaws out, it will create an excess of water in the drain pan and possibly cause an overflow. 

If you see ice on your coils or anywhere near your unit, the first thing you want to do is turn off your AC unit by flipping the breaker. Then look for the root of the issue and fix it. If you’re unable to figure out why your coils froze, you will need to call an HVAC technician to come and help because there could be a much bigger problem going on. 

How Much Does It Cost to Fix Your AC Drip Pan?

If you need to replace your drain pan, a new one will cost anywhere from $350-$800 depending on the make and model of your air conditioner. If something else is causing the problems with your drip pan, like frozen evaporator coils, it could be more of an expensive fix.

One thing that is certain is that maintenance is always the cheapest route. Regularly servicing your air conditioner can help avoid frozen coils, clogged drain pipes, and rust buildup, and can save you loads of money in the long run.

Should You Hire a Professional?

Drain pan problems are easy to fix on your own if they are caught early. I would recommend trying some of the DIY methods I mentioned above to clean out the condensate line first.

If the problem is as simple as a clog, you will probably be able to fix the issue without the help of a professional. Even replacing the drain pan is easy enough to do on your own. 

However, if you don’t catch it in time and the water overflowing from your drain pan has caused damage to the electrical components of your air conditioner, you will need to call a professional to fix it.


In conclusion, don’t be alarmed if you hear water sounds from your A/C or if water is coming out of your air conditioner’s condensate line. On the contrary, you should be alarmed if water is not coming out!

If you are having issues with your air conditioner’s drain pan or its drainage system, hopefully, you are able to troubleshoot it with some of the methods in this article and get your unit back in working order.

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