How to prevent damage from a clogged condensate drain line

We all know how humid the summer can be. And it's because of this humidity that your home could run into costly water damage.

If your home's condensate drain line becomes clogged with dirt, debris or a buildup of rust or algae – this can cause major damage.

How is that possible? We’ll explain:

What is a condensate drain line? A condensate drain line helps remove excess water that drips off of your air conditioner's inside unit.

Think of this - when you have a glass of water with ice in it, the humidity in the air surrounding the glass is cooled down. The cooled moisture in the air forms those little droplets on your glass. That's condensation.

The same thing happens with your air conditioner. When your air conditioner removes humid air from the living space through your return vents to be cooled, water droplets form on the evaporator coils.

That water needs to go somewhere. Enter - the condensate drain line. This drains the water to a floor drain, laundry tub, sump pump, condensate pump or a small 3/4 inch PVC piped directly outside your house.

Why does this matter? Imagine if that drain line was clogged: all that water formed by condensation has nowhere to go and backs up into your home.

This creates a variety of problems including:

  • Water damage
  • Creating a breeding ground for mold, mildew, virus and bacteria
  • Causing a possible electrical issue if the water drips onto any electrical components

The source of the clogs is usually algae, which thrives and grows in dark, damp areas. Other sources can be dirt, dust, debris, or insulation fibers in the main indoor coil drain pan.

What are signs that my condensate drain line is clogged? Most homes have a secondary drain line that drips only when your main line is clogged. This drain line is higher and towards the roof line or attic. If you see this leaking, you'll know that the main drain line is clogged.

If this secondary line becomes clogged, and your air handler (the inside portion of your air conditioning unit containing the coil and fan) or indoor coil is located in your attic, you'll notice water leaking from your ceiling.

If this is the case, call an air conditioner professional to unclog the drain for you.

How to keep condensate drain line clogs from causing a problem: There are plenty of things you can do to keep clogs from causing water damage in your home:

Get annual air conditioner maintenance - A typical air conditioner tune-up includes checking your drain line so that there are no clogs and clearing the drain line as a precautionary measure.

Make sure drains lines are properly pitched (angled down) - water flows downhill, so you need to make sure the drain line is properly pitched. Also, ensure drain lines don't sag and be sure not to store items on top of drain lines in your attic.

Use a wet/dry vacuum - connect the hose to the drain line to suck out any algae or debris that has built up in the drain line.

Keep an eye on the secondary drain line - next time an air conditioner contractor is at your home, ask him or her where your secondary drain line is. If it's dripping water, you know you have a problem.

Install a safety switch - you can install a safety switch on your drain line that automatically shuts off your AC if the drain line is clogged. This helps you avoid expensive water damage.

How to increase energy efficiency

Sealing leaky ducts may be the biggest single thing you can do to improve efficiency, but replacing dirty filters, cleaning the coils and keeping the right charge and airflow will help as well.

Another thing to do is to make sure the outdoor (condenser) unit is not so hidden from sight that its airflow is blocked or that leaves or other matter are not clogging it.

If you are replacing the air conditioner, look to buy high efficiency equipment. The most generally known efficiency rating is Seasonal Energy Efficiency Rating (SEER). SEER 13 is the minimum efficiency you should consider, but higher efficiencies are likely to be quite cost effective.