Skip to Content

What Happens When Your Condensation Drain is Clogged?


If youandrsquo;ve ever taken a look at the indoor unit of your HVAC system, youandrsquo;ve probably noticed that thereandrsquo;s a large metal pan sitting beneath it. This is known as your drain pan and its job is to capture water that drips out of your air conditioner. This is a perfectly normal part of the cooling processandmdash;as water vapor particles come into contact with your freezing cold indoor coil, the water quickly turns from gas form to liquid form, eventually accumulating into drops. Those drops eventually drip off the coil and down into your drain pan where they are safely collected and carried away via a drain line connected to the bottom of the pan.

You may not think your drain line is all that importantandmdash;after all, it only has to carry away a small amount of water that your air conditioner naturally produces as a byproduct. However, your drain line can become clogged with debris like pet hair, dirt and dust and this could present a problem.

What Happens When Your Drain Line Clogs?

When your drain line clogs, the water that your air conditioner produces has nowhere to go. Instead, it simply sits in the line or in your drain pan and slowly evaporates back into the atmosphere, increasing your indoor humidity levels. Too much humidity in the air is already an annoying-enough problem, as it can result in sticky and uncomfortable feeling air in your home. However, it can also contribute to issues like mold and mildew growth, which cause a lot of health problems on their own.

Likewise, sitting water or water vapor around your air conditioning unit could result in further corrosion or rust of metal parts that make contact with the water or are located near it. Rust shortens the life of your system and could result in earlier replacement, which is an extremely expensive issue that could be easily avoided. Thus, you really donandrsquo;t want water sitting around in the bottom of your drain pan.

However, thereandrsquo;s another issue that could also come up: when the water canandrsquo;t drain away, it will simply continue to accumulate as your air conditioner runs. The more water that your system extracts from the air, the more water will drop down into the pan, and the more your pan will fill up. Eventually, a completely blocked drain line will cause the water in your drain pan to overflow, resulting in potentially catastrophic damage to your home.

Water that overflows the pan can cause damage to drywall, including staining your walls, weakening their structure and even damaging your floors, furniture or anything else that may be in the vicinity. Your electrical system could also be impacted if water finds its way to an exposed wire or other issue. And like we mentioned previously, this water could also foster mold and mildew growth and even do so faster than water vapor or humidity ever could.

Thus, if you find that water is building up in the drain pan beneath your indoor HVAC equipment, itandrsquo;s extremely important that you investigate the issue as soon as possible. More often than not, the issue is simply that a collection of dirt, dust, lint and other common materials have accumulated in your drain line, creating a clog which can often be dislodged using a thin stick or even a jet of water, freeing the line and allowing the condensation to drain away with ease.

Elsewhere on Our Blog

Elsewhere on our blog this month, we took a look at another common question that our air conditioning and heating technicians receive: “How often should I replace my air filter?” Your air filter is an extremely important part of your HVAC system, but we find that many people simply donandrsquo;t change their filter often enough, and that could lead to all sorts of issues from inefficiency to shortened lifespan and even breakdowns like a frozen system. The answer isnandrsquo;t as straightforward as many people expect, and we took a closer look at why, but a good general rule of thumb to follow is to check your filter every month for yourself, and then replace it as necessary when you find itandrsquo;s getting too full of dirt and other debris.

We also took a closer look at an idea that people who work in an office may have heard before, but never actually researched the truth for themselves: do fluorescent lights cause health problems? The results are somewhat mixedandmdash;while science does indicate that there could be some physical impact of continual exposure to these particular types of light fixtures, theyandrsquo;re not the most harmful out there, and in fact their smaller, energy-efficient counterparts known as compact fluorescent lights (CFLs) can actually expose you to significantly greater levels of radiation. Read the rest of our blog to learn more for yourself:

Whether you need your heating and cooling equipment serviced or you need a light fixture repaired or replaced, make sure you call our experienced team at Valley Heating, Cooling, Electrical and Solar at for a job done right. Dial (408) 868-5500 to schedule yours.

Share To: