Condensate Is Normal — Leaking Is Not
Rheem and Ruud high-efficiency furnaces (90%+ AFUE condensing units, including many R96 and similar models) are built to pull extra heat out of the exhaust. As they do, water vapour condenses into liquid inside a secondary heat exchanger. That condensate is slightly acidic and should drain quietly away through a trap, hoses, and frequently a condensate pump.
The key distinction: producing water is normal, but leaking onto the floor is not. If you see a puddle, the drainage path is blocked or broken, or the water is actually coming from the air-conditioning coil mounted above the furnace. Identifying which one is at play is the first step to a clean fix.
Top Causes of a Rheem Furnace Leak
Clogged condensate trap or drain line. Rheem furnaces use an internal trap that collects debris and biofilm over time. When it plugs, water backs up and spills out — by far the most common cause.
Condensate pump failure. Many Lower Mainland installs route condensate to a small pump because the drain is above the floor. A stuck float, failed motor, or unplugged cord causes overflow.
Loose, cracked, or disconnected tubing. The flexible drain lines and trap connections can slip or crack, particularly after maintenance.
AC evaporator coil drainage. In cooling season, the coil in the upper cabinet sheds condensate. A clogged coil pan or drain line drips onto the furnace and looks like a furnace leak.
Secondary heat exchanger corrosion. Less frequent, but acidic condensate can eventually corrode the exchanger, causing it to weep. This requires professional inspection and is not a DIY repair.
Safe Checks Before Calling a Technician
Switch the furnace off at its service switch and grab some towels. Find the highest point where water appears — the trap, a hose joint, the pump reservoir, or the cabinet above (pointing to the coil). That tells you the likely source. It also helps to note *when* the leak happens: only during cooling season points to the AC coil, while year-round or heating-season leaks point to the furnace's own condensate path.
If you have a condensate pump, confirm it is plugged in and cycling; a silent pump with a full reservoir is your answer. Inspect visible hoses for kinks, splits, or disconnections you can gently reseat, and check that the trap is seated and not cracked. Dry the area fully, then watch for a minute or two so you can confirm whether the leak is ongoing or was a one-time overflow.
Do not pour drain chemicals through the furnace, run it with water touching electrical components, or open the burner or heat-exchanger compartments — those are sealed, gas-side areas that require a certified technician. If water is more than a slow drip, leave the furnace off and call 604-359-1081 for service.
What Happens If You Ignore It
Because Rheem condensate is acidic, a persistent leak corrodes the furnace base, rusts burners and the control board, and can stain or rot the floor and ceiling below. In Greater Vancouver's wet climate, lingering moisture around the cabinet also invites mold.
There is a safety dimension too. Water pooling in the wrong area can affect the inducer or pressure switch and, in turn, combustion. If a leak appears alongside soot, a sounding CO alarm, or a gas odour, treat it as an emergency: leave the home and call FortisBC at 1-800-663-9911 or 911, then call us. Otherwise, fixing the leak early keeps a small repair from turning into a heat exchanger replacement.
Rheem Furnace Service in the Lower Mainland
Furnaces, including all Rheem and Ruud models, are serviced by our parent company, CanroHeat. Our Red Seal–certified technicians work throughout Vancouver, Burnaby, Surrey, Richmond, Coquitlam, and the North Shore. We clear and re-trap condensate drains, replace failed pumps and cracked tubing, service AC coil pans, and inspect heat exchangers, then verify proper draining and venting before we go.
Costs depend on the cause, so we diagnose first and give an exact, written price — never a guess. While we are there, we will also point out anything trending toward a future leak, such as a tired pump or a trap due for cleaning, so you can plan ahead instead of waiting for the next puddle. Call 604-359-1081 for a quote specific to your Rheem furnace, or to arrange same-day or weekend repair.