Furnace Leaking Water? Here’s How to Fix It

furnace heating unit on wall in an old basement

Finding unexplained leaks and standing water in your home is every homeowner’s nightmare. If your furnace has recently started leaking water, that’s a problem that needs immediate HVAC repair. Here’s what you can try before you call an HVAC service.

How Much Water Around Your Furnace is Too Much?

In short, you should never see water on or around your furnace.

Your air conditioner produces a lot of condensation around your evaporator coil, which explains why furnaces have moisture around them in the first place. When your furnace is working properly, the only sign of moisture should be an occasional dripping sound. If you do, you should remedy the situation right away. We’ll get into a quick DIY fix below, which you can try instead of immediately reaching out to an HVAC repair service.

How to Prevent Furnace Leaks

The best way to prevent a leaky furnace is simple: get regular preventative maintenance on your air conditioner and HVAC system. Keeping up on regular repairs and maintenance gives you the chance to identify issues before they have time to become big problems. It’ll also prolong the life of your system without the need for costly repairs. By taking care of your air conditioning system, you’ll eliminate most risks for water damage and other unpleasant complications.

What to Do if You Notice a Leaky Furnace

Shut Off Your Furnace and Coil

Your shutoff switch should look like a regular light switch positioned near your furnace. If you can’t find that, flip the breaker.

Mop Up the Leak

Before you start trying to fix the underlying problem, make sure you get rid of any standing water on or around the furnace. It can be dangerous and risk damage to your home.

Check the Filter

Can air still flow easily through your filter? If not, it’s time to change it.

Use a Water-Safe Vacuum (Like a Shop-Vac) Around the Drain Line

This will remove any debris or potential clogs. When you’re done, you can turn your AC back on. Stick around for a while to keep an eye on it so you’ll notice if the furnace starts leaking again.

Pour Water Into the Condensate Pump

If the pump starts working, that indicates the drain line is clear now. You’re good to go! Problem solved.

If the pump doesn’t react to this, that’s a sign of a mechanical failure. A professional will need to come take a look at the problem.

If you try all these steps and your furnace is still leaking or pouring water into the condensate pump doesn’t trigger a reaction, call your trusted HVAC repair service to come take a look. Just fixing a leaky furnace generally costs about $300, a pretty manageable repair.

But if your system is old, increasingly needs frequent repairs, has other concerning behavior, or if your energy bills are climbing, it might be time to talk about replacing the whole system. Your service provider can talk you through your options.

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