AC Leaking Water? Here’s Why and How to Fix It!

AC Leaking Water? Here's Why and How to Fix It

Is your AC leaking water inside? Well, it shouldn’t be! Leaky air conditioners are a problem, but it’s not the end of the world if dealt with correctly.

Though if not caught early enough, a simple leak can become a nightmare.

A small water leak can damage ceilings, walls and floors and can be a starting point for mold growth to take over your home, destroy your indoor air quality, and give you a huge repair bill.

As an HVAC service company, we know a little about air conditioner issues, so we can help give you some insight into problems and fixes to ensure your home remains comfortable.

💧 Where Is This Water Leaking From?

Central AC in a residential home

A modern air conditioning system cools your home through heat transfer.

It absorbs the heat from the warm air in your home and transfers it to the outdoor unit, where it dumps it and starts the process over again.

This heat transfer occurs between the indoor and outdoor units.  

Within the indoor unit is an evaporator coil. This AC unit coil is what absorbs the heat in the air.

As the hot air blows over the coil, condensation can form, similar to a cold glass of water on a humid day.

This moisture drips into a drain pan that’s connected to a condensate drain line that flows outside. 

Well, that’s how an air conditioner is supposed to work!

So what happens when this doesn’t happen and water leaks into your home?

Keep reading to find out how water can leak in your home and how you can fix it…

AC Leaking Water Reason No. 1 – Damaged Drain Pan

Central AC indoor air handler showing drain pan and condensate drain line

The drain pan or drip pan is the tray that sits below your evaporator coil to collect the condensation so it doesn’t leak everywhere. Pretty obvious, right?

Some systems can have a secondary drain pan that’s located underneath the indoor air handler to catch any additional leaking water.

So if you have a damaged or rusted drain pan, you will have problems.

🧰 The Fix!

First, check that you do not have a disconnected drain line. That’s a simple fix.

If it’s not disconnected, it’s probably the drain pan.

There isn’t much you can do here besides replacing the drain pan.

Sealing it is only a short-term fix, and you will have the same problem again soon. 

Cheaper galvanized steel drain pans don’t last long, so you could opt for a more expensive stainless steel one or a polymer drain pan.

Either way, it’s time to call your local HVAC technician to get it replaced.

You can also fit a float switch in case of an overflowing drain pan.

This will shut off your AC before the water leaks everywhere.

AC Leaking Water Reason 2 – Clogged Condensate Drain Line

The condensate drain line is what carries the water from your drip pan and funnels it outside.

A clogged drain line will back up the water, causing it to leak.

Dirt and debris that’s bypassed your air filter (which is probably dirty and needs replacing) can accumulate over time and makes its way into the condensate line.

Also, backed-up water has weight, and the vibrations of your air conditioner can cause the clogged condensate drain line to disconnect from the drain pan.

🧰 The Fix!

Time to blow out the drain line! 

You can use a water hose or compressed air at low pressure or a long wire brush to flush it out to help prevent water damage to your home.

Cleaning out your drain line with bleach is a good idea if you see mold or mildew growing in the drain line.

AC Leaking Water Reason 3 – Failed Condensate Pump

If your AC and furnace are located in your basement, it has a condensate pump fitted to it.

This is what pumps the water from your HVAC system to an outside drain.

So naturally, you will have a problem with a broken condensate pump.

🧰 The Fix!

Replace the pump! This is an easy one for a keen DIYer.

If you’re not sure it’s the pump or you are not comfortable replacing it, call your local friendly HVAC contractor to replace it.

AC Leaking Water Reason 4 – Frozen Evaporator Coil

A frozen coil is caused by two main issues – low refrigerant or reduced air flow. 

Now depending on what type of air conditioner you own will depend on where you will have the water leak.

If you have a central air conditioner, your evaporator coil will be in the indoor air handler, normally in a basement or a garage. 

In the case of a ductless air conditioner, it’s located within the air handler that’s mounted on the wall in each room.

A Ductless AC is one case where an air conditioner leaking water is a big problem. 

Nothing worse than dripping water inside your living room…

As a frozen coil melts, it releases an extraordinary amount of water which might overwhelm your drainage system.

🧰 The Fix!

In our experience, a frozen evaporator coil is best left to the experts.

If you damage a coil while defrosting it, you will be left with a large repair bill. 

PRO TIP: Never chip away at a frozen AC coil with a sharp object! You can easily damage the coil, which will then require replacement. It still may not be cost-effective to replace, and you might have to replace your entire air conditioner.

If you want to learn more about the signs and how to deal with them, then we have the article for you: How to Deal with Ice Build up on an AC Unit

Keeping your AC clean is important for it to function correctly. Ensure you understand the importance of a clean evaporator coil. Check out: The Importance of a Clean Evaporator Coil

Air Conditioner is Leaking Water Reason 5 – Dirty Air Filters

Phyxter HVAC Tech changing filters

A clogged air filter is the most common cause of a range of AC problems.

It’s also the cheapest to manage and fix yourself.

As highlighted above, a dirty air filter reduces airflow and can cause your evaporator coil to freeze.

🧰 The Fix!

Replace your dirty filter!

Depending on your requirements, you should check your filter at least once a month and replace a dirty air filter every two to three months.

There’s more to air filters than you think.

We have put together a few resources below for you to learn more about the science of air filters.

Air Filter Guide. MERV Filter Ratings and What They Mean For Homeowners

Top 5 HVAC Problems Caused by a Dirty Air Filter

Furnace Filter Location — Where is It?

Furnace Filter Direction – Which Way Is the Right Way?

AC Leaking Water Reason 6 – Refrigerant Leaks

Phyxter tech checking refrigerant levels

Your air conditioner only works efficiently when it has enough refrigerant in the system.

It’s a closed system, so you will only have a problem when you have a refrigerant leak.

It sounds counterintuitive, but low refrigerant levels will cause your air conditioning unit to run cooler than it should, contributing to a frozen AC coil. 

You will notice if you are running low on refrigerant, if: your AC isn’t cooling as well as it used to, or if you hear a hissing or bubbling sound coming from around your AC system.

Check out our next article on AC refrigerant leaks to learn more.

🧰 The Fix!

If you catch your refrigerant leak in time before it worsens, you will likely will be able to repair it. If not, you will have to spring for a new evaporator coil, which can be expensive.

This is definitely a job for a qualified technician. Refrigerant is toxic and illegal to vent into the atmosphere, so it requires some finesse to handle. 

Want to learn more about refrigerants? Check out: What is Freon? Everything you Need to Know About Freon, Refrigerants and CFCs.

⭐ Final Thoughts

Having your AC unit inspected regularly can prevent these problems from occurring.

We always recommend a regular maintenance schedule to our customers to avoid preventable problems such as an air conditioner leaking water.

If your AC is leaking water and you are still not sure how to deal with it, call your local HVAC company. 

If you live in the Okanagan region, Phyxter Home Services should be your first call to get your air conditioner blowing cool air this summer.

Don’t deal with your AC leaking water inside; call the HVAC service experts from Phyxter today!

Russell Jones

VP of Operations @ Phyxter and Home Improvement Specialist

About our blog

Phyxter (pronounced Fix-ter) is a national home services brand specializing in Residential HVAC, Electrical and Plumbing solutions.

Phyxter is laser-focused on writing the best articles and guides to empower homeowners to get the best out of their homes.

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