How To Clean AC Drain Line With Bleach

The air conditioner does a lot more than lowering your room’s temperature. It is also responsible for removing moisture from the air. 

However, you might find that the condensate drain line is clogged every once in a while. To ensure your unit’s peak performance, it is essential to clear the AC drain line regularly. You can do that by pouring down some bleach to clean the line.

This article will help you understand how to deal with a clogged drain line without calling an AC maintenance professional.

The Basics of a Blocked AC Drain Line

Air conditioners work by pulling moisture from the atmosphere, thus reducing humidity in your room. The evaporator coil inside the AC removes any water particles from the air and stores them in the drain pan. It is further connected to a small drain line that transfers the condensation outdoors.

When you go outside and see the back of any air conditioning unit, you will spot a line with dripping water. It is also known as the AC drain line and is prone to water leakage. 

If you don’t notice the drain line dripping, it is time to look for clogs. With the onset of storms and heavy rainfall, plenty of leaves, debris, and other airborne particles get stuck in the drain line.

Now, when the moisture from the evaporator coil drips down the AC drain lines, it picks up all such substances. As a result, the watery litter mixture accumulates at the pipe’s bottom. 

Additionally, the moisture in the drain line can also lead to mildew, algae, and mold growth. If left untreated for a longer time, such matter can line up inside the tube and slow down the passage of water droplets.

Is It Safe to Pour Bleach Down the AC Drain? 

Yes, it is safe to pour it down the AC drain if done correctly. Bleach has antimicrobial properties that can help clear the pathway to your unit’s condensate drain pipe. But you need to be mindful about not pouring it closer to the evaporator coil. 

How Bleach Helps Clean a Blocked AC Drain Line? 

Needless to mention, clearing up all the clogs in your AC drain line should be on top of your to-do list before the summer arrives. But first, let’s understand how bleach can help with that. The inside coating of the pipe develops bacteria growth due to the constant moisture presence. 

Using a bleach solution or tablet will help remove all mold and bacteria. However, do note that it cannot clear a heavily blocked drain line. It is a good option for mild blockages or prevention. 

How Often to Pour Bleach Down the AC Drain? 

You can use it twice a year when the summer season begins and ends. It is corrosive in nature and can harm the metal components inside the air handler if used more frequently. 

The frequency of use will vary as per any individual’s household needs and geographical region. If you use the air conditioner at all hours for most of the year, you will need to clean the drain line more often. On average, a minimum of 2 cups per season should be enough. 

The evaporator coil inside the condensate drain line comprises metals like copper or aluminum. Now, if you empty bleach down the line and it backs up due to a stubborn clog, it will come in contact with the coil’s surface and corrode it. 

How Do You Pour Bleach Down the AC Drain?

Before beginning the process, you must carefully cover your eyes, nose, and hands. Bleach can be harmful to the human body. Now, mix warm water with bleach in a cup. Slowly empty the solution down the drain line. Ensure that the solution doesn’t flow backward, or it may harm the air handler. 

Where to Pour Bleach in the AC Drain?

The drain line for your air conditioner unit is present on the outer wall, near the air handler unit. Here, you will spot a PVC pipe with a closed lid at the end. The drain line access point is where you need to add it in.

How Much Bleach to Add to AC Drain Line? 

When pouring bleach, you have to be very careful about the quantity. Otherwise, you might end up damaging the evaporator coil. You can mix 1/4th cup of bleach with 1 cup of warm water for optimum results.

How to Clean AC Drain Line with Vinegar?

Most people don’t realize that calling for the maintenance company is unnecessary each time your condensate drain line is clogged. If bleach is unavailable, you can also use another easily found kitchen ingredient, i.e., vinegar.

Materials Required to get Started – White vinegar, rough cloth, warm water.

Step 1 – Turn Off Your Air Conditioning Unit

Before beginning, turn off the system to avoid unwanted damage and reduce the risk of electrocution. Ensure to turn off at both breaker and thermostat levels.

Step 2 – Locate the Condensate Drain Pipe

The condensate drain line is a PVC pipe near the condensation unit or a prominent box-like structure for outdoor AC units. This pipe is usually attached to the wall.

Step 3 – Remove the Debris

Check the drain line access point and remove any physical debris you can spot in it. These drains can also have a T-shaped covering on the top.

Step 4 – Pour the Vinegar

Slowly pour a quarter cup of distilled white vinegar down the clogged condensate drain line through the access point. This vinegar solution helps unclog your drain quickly.

Step 5 – Switch the Power On

Let it sit for half an hour and flush the pipe with warm water. Once everything is clear, you can switch your AC back on. For best results, you should repeat this process once a month.

Clean AC Drain Line – Bleach vs. Vinegar

To deal with a clogged AC drain line, there are several methods you can use. However, you must be careful while dealing with vinegar or bleach solution.

Window Units

Window air conditioner units are set up so that the exterior portion is attached to the outside wall. Pouring bleach here will potentially damage any surface or plants beneath and damage the vinyl shingles. 

Toxic Odor

Bleach or vinegar solutions have a characteristic rotten odor that is quite unpleasant. To ensure that your AC does not circulate chemical-infused air, you should flush the condensate drain with water repeatedly. 

ABS Plastic and PVC Pipe

If your AC drain is made of PVC pipe, you should avoid using bleach as it can melt away its inner lining. It can also break the cement joining between the drain pan and line. 

Tell-Tale Signs of a Blocked AC Drain Line 

If the drain line clogs are detected sooner, you can call for routine maintenance or work on resolving the matter yourself. Here are a few signs to look for in such cases.

Overflowing Water Drainage Pan – Most AC units include an external pan designed to collect the moisture in case of drain line clogs. You can check the water level inside the pan, and if it is full, there’s a high chance of clogging.

Standing Water – You must have noticed that water pools around the external air conditioning unit at times. In such cases, try to find out the source of leakage. There’s a drain clog to deal with if it comes from inside the AC.

Mobile Notifications – Most latest units are smart appliances and will alert you when the drain clog is detected. This feature can effectively improve the peak performance of your AC by ensuring that no internal damage goes unnoticed.

Mold Odor – If there’s a musty smell in the environment, you must look for the source of water damage or mold growth. One such case could be a clogged drain line that will cause a foul odor to spread inside your house through the AC unit.

Alternative Ways to Clean a Blocked AC Drain Line

Cleaning the drain line with bleach is not always the most suitable method. The chemical can end up harming the evaporator coils inside the condenser unit. The evaporator coil is usually copper or aluminum and can react badly to chlorine in the bleach solution.

But not cleaning your AC drain line regularly can cause serious harm to the air condition system. In this case, you can follow alternative methods to unclog the drain line. Here are a few of the common ways to get your drain line clean:

Manual Cleaning

One of the safest and easiest ways to keep your indoor air handler working in an optimum condition is by checking the AC drain lines for debris. With storms, several airborne particles, leaves, wrappers, etc., get stuck inside the pipe entry.

You can go outside, check the access point, and attempt to clear away any such blockage. Doing this every once in a while will ensure that no matter travels down the drain to cause more issues to affect the evaporator coil.

Using Shop Vac and Water

You can join the shop vac hose with the drain pipe. If you cannot secure the connection, tie them using duct tape. 

Now, switch the vacuum on. Get some water and pass it through a funnel down the drain. It will allow the vacuum to suck all the water and impurities passing through the drain line. But if the clog remains, water will flow backward and accumulate on the floor.

Drain Snake

If the clog persists, you can try using a drain snake inside the pipe. But be mindful about maintaining a safe distance from the air handler, or you might unintentionally damage the evaporator coil.


You can take 1/4th cup of vinegar and pour it down the drain line. Let it sit for 30 minutes, and then flush water inside the pipe.

How Often Should You Treat Drain Lines? 

Some people will notice that their drain lines are getting clogged way too often. It could happen due to typical stormy weather and other reasons as well. There are fewer chances of blockage for people who use the air conditioner for a limited time. 

If you have decided to use condensate bleach tablets, you will find the recommended frequency of use mentioned on the back. Usually, you should clean your drain line every once in 6 months. If you start noticing signs of drain line clogs before that, it is best to treat it yourself or call for maintenance.

How to Prevent Clogged AC Drain Line in Future? 

There are several ways to ensure that the condensate drain line does not get clogged. Here are a few of them:

Regular Cleaning of AC Unit – You should call the professionals to clean your entire air conditioning system at least once or twice a year. Doing so will ensure that there are no significant clogs in the unit.

Premium Quality Air Filters – You can choose to settle for cheaper options, but investing in good quality air filters can help restore your AC unit’s condition. Such filters help ensure that the evaporator coil works without any hitches.

Ideally, you should replace these filters every once in 3 months. But you can do it more frequently if there are any pets or smokers in the house.

Use Vinegar – It will help clean your drain lines and eliminate any bacteria growth inside the pipeline. The acidic nature of chemicals will help unclog the drain.

Regular Maintenance – Instead of waiting for the condensation pipe to start leaking on the floor, you can prevent clogs by scheduling timely maintenance. Most AC companies and service centers can help get a reliable technician to your house.


Every appliance in your house needs proper attention. So does your air conditioner. The condensate drain line can get clogged by removing moisture from the air. As a result, the AC unit might not function properly. 

You can clear your drain pipe using simple solutions. One of the methods is to pour bleach down the AC drain line. It is straightforward and can be carried out at home easily. 

So, what are you waiting for? Go look at the condensate drain pipe and ensure that it is not clogged.