Why Is My Heat Pump Leaking Water?

Key Points

• Heat pump leaks are relatively common and usually inexpensive to fix when caught early — but ignoring them leads to water damage, mold growth, component failure, and electrical hazards.
• According to the U.S. Department of Energy, heat pumps require regular maintenance to operate efficiently — most leak-causing issues (dirty coils, clogged drains, worn pans) are directly preventable with routine annual or semi-annual service.
• Five common causes of a leaking heat pump: dirty evaporator coil, frozen evaporator coil from low refrigerant, clogged condensate drain, cracked overflow pan, and poor maintenance history.
• A frozen evaporator coil is the most urgent cause — if you see ice on the unit, reduced cooling output, or rising energy bills together, shut the system down and call a technician rather than letting it continue to run.
• Heat pumps used year-round in Central Texas should be serviced twice a year — once in spring before cooling season and once in fall before heating season — due to the system’s continuous dual-season operation.
• A simple drain clog or coil cleaning is an inexpensive same-day repair; a water-damaged control board or shorted electrical component from an ignored leak is not.
• Contact Comfy Air AC and Furnace Repair for fast heat pump leak diagnosis and repair throughout San Marcos and Central Texas.

 

Heat pumps play a major role in keeping your home comfortable year round. They move heat in and out of your home depending on the season, using refrigerant to keep temperatures just right. So when your heat pump begins leaking water, it’s understandable to feel concerned — but the good news is that most leaks are easy for a trained technician to repair.

Below, we’ll walk through the most common causes of a leaking heat pump and why fast action matters.

How Serious Is a Leaking Heat Pump?

Compared to other HVAC issues, a leaking heat pump is not the worst problem you could face. It’s a relatively common issue that professionals can fix quickly.

However, you should contact a technician as soon as you notice the leak. Ignoring the issue can lead to:

• Water damage — moisture that pools around or inside the unit can saturate flooring, drywall, and subflooring before it becomes visible
• Mold and mildew growth — standing moisture inside the unit or in surrounding materials creates ideal mold conditions within 24–48 hours
• Component failure inside the unit — water reaching the control board, capacitor, or electrical connections causes corrosion and short circuits
• Electrical hazards or short circuiting — water and electricity are a dangerous combination; never ignore a leak near electrical components

A simple leak is inexpensive to fix. A damaged or shorted-out system is not.

How to tell where the water is coming from: Before calling a technician, note where the water appears — under the indoor air handler, around the outdoor unit, or both. Water under the indoor unit most often indicates a clogged condensate drain or cracked overflow pan. Water around the outdoor unit during heating mode can be normal defrost condensation. Water at the outdoor unit during cooling mode alongside reduced performance typically indicates a refrigerant or frozen coil issue. This information helps your technician prepare for the service call.

Dirty Evaporator Coil

The evaporator coil collects moisture from the air as part of the cooling process. This water normally drains into a pan. When the coil becomes dirty, moisture can’t flow through properly — causing water to pool and leak.

Regular tune-ups help prevent dirty coils. If buildup occurs, professional cleaning can resolve the issue.

How dirt accumulates on coils in San Marcos homes: Central Texas’s spring cedar pollen season, combined with dusty conditions during dry summer months, accelerates debris accumulation on evaporator coils compared to regions with milder air quality. A coil that might need cleaning every two years in a cleaner-air environment may need attention annually here. A dirty coil also reduces cooling efficiency — the same debris that causes water pooling also insulates the coil from absorbing heat effectively, raising energy bills. Heat pump maintenance that includes coil cleaning is the most direct prevention.

Frozen Evaporator Coil

Low refrigerant levels can cause the evaporator coil to freeze. As the ice begins to melt, the thawed water may appear as a leak.

Signs of a frozen coil include:

• Visible ice buildup on the refrigerant lines or the indoor coil
• Reduced cooling — the system runs but can’t reach the set temperature
• Higher than normal energy bills — the system works harder to compensate for lost refrigerant capacity

A technician can safely thaw the system, repair any refrigerant issues, and prevent future freeze-ups. Heat pumps used year-round should be serviced twice a year.

What to do if you suspect a frozen coil: Turn the heat pump off at the thermostat and switch the fan to “On” mode to circulate room-temperature air over the coil — this speeds thawing without running the compressor. Do not attempt to chip or scrape ice from the coil. Once thawed, the system needs a refrigerant level check and leak test before restarting. Running a heat pump with low refrigerant after thawing will refreeze the coil and risk compressor damage. Call Comfy Air for a heat pump repair visit to address the root cause.

Clogged Condensate Drain

The condensate drain carries moisture away from your heat pump. Over time, dirt, dust, and debris can block the line.

When the drain is clogged:

• Water can’t escape the system
• Moisture overflows inside the unit
• Puddles form around the heat pump

Routine tune-ups and inspections help prevent clogs and allow technicians to check for mold growth inside the drain system.

DIY prevention between service visits: Pouring a cup of white vinegar down the condensate drain line every 1–2 months during cooling season helps prevent the algae and mold growth that causes most drain clogs. The drain access point is typically a small PVC pipe near the indoor air handler. This is one of the few genuine DIY maintenance steps that makes a real difference — but it doesn’t replace professional inspection, which includes checking the entire drain pan and line for damage, proper slope, and mold growth that vinegar alone doesn’t resolve. Schedule a heat pump tune-up to keep the full drain system in check.

Cracked Overflow Pan

Heat pumps collect humidity from the air, and the moisture drips into an overflow pan. Over time, this pan may rust, corrode, or crack.

A cracked pan allows water to:

• Leak onto the floor — causing water damage to the area around the air handler
• Leak back into the heat pump — causing damage to internal components

Homeowners should have their heat pumps in San Marcos inspected annually to ensure pans, drains, and coils are functioning correctly.

Why pans fail faster in some homes: In humid Central Texas conditions, overflow pans that are rarely or never emptied accumulate standing water between drain cycles — accelerating rust and corrosion. Metal pans in systems over 8–10 years old are at the highest risk. Some newer systems use plastic drain pans that resist corrosion but can crack from temperature cycling over time. During any HVAC inspection, the technician should visually inspect the pan for rust staining, hairline cracks, and any evidence of past overflow.

Poor Maintenance

Skipping routine maintenance is one of the biggest contributors to heat pump leaks. Without regular service, dirt buildup, worn parts, and minor issues go unnoticed until they become bigger problems.

A technician will:

• Inspect and clean the system — coils, drain pan, and condensate line
• Identify early signs of leaks — hairline cracks, corrosion, and deteriorating seals before they cause visible water
• Perform necessary repairs before damage occurs — catching a $50 drain cleaning before it becomes a $500 water damage situation

Routine care helps keep your heat pump efficient, reliable, and leak-free.

The twice-a-year maintenance schedule for Central Texas heat pumps: Because San Marcos and the surrounding area use heat pumps for both cooling (April–October) and heating (November–March), the system runs nearly year-round. This continuous operation means components wear faster and require more frequent attention than in climates where heat pumps run seasonally. The industry standard for year-round heat pump climates is two service visits per year — spring (before cooling season) and fall (before heating season). A single annual visit leaves half the year’s wear uninspected heading into your heaviest use period.

Key Takeaways

A leaking heat pump in San Marcos is almost always caused by one of five issues: a dirty evaporator coil blocking moisture flow, a frozen coil from low refrigerant, a clogged condensate drain, a cracked or corroded overflow pan, or neglected maintenance that allowed small problems to grow. Most of these are inexpensive to fix when caught early — the cost escalates when water reaches electrical components or causes structural moisture damage. If you see ice on the unit, turn it off immediately and call a technician rather than letting it continue to run. Central Texas heat pumps should be serviced twice a year given their nearly year-round operation. Contact Comfy Air AC and Furnace Repair for fast, reliable heat pump leak diagnosis and repair throughout San Marcos and Central Texas.

Don’t Ignore the Equipment That Keeps You Comfortable All Year

Comfy Air provides trusted heat pump repair and maintenance in San Marcos. Our technicians are trained to diagnose leaks, fix refrigerant issues, clean coils, and keep your system running flawlessly.

Contact Comfy Air today to schedule your HVAC service.