Boiler Leaking Water — Causes, Dangers, and What to Do
Published: July 14, 2026 — CANRO Heating & Cooling — Greater Vancouver, BC
Is a Leaking Boiler Dangerous
A leaking boiler can be dangerous depending on the source. Water near electrical components creates a shock hazard. A leak from the heat exchanger may indicate corrosion and potential carbon monoxide risk. If water is pooling around your boiler, turn off the electrical supply at the breaker before touching anything. Call a licensed technician.
Common Sources of Boiler Leaks
Pressure relief valve discharge is the most common. Pump seal failure allows water to seep from the pump shaft. Heat exchanger corrosion causes pinhole leaks. Condensate pipe leaks from acidic condensate corroding connections. Loose pipe compression fittings are the easiest fix.
Emergency Steps
Turn off the boiler at the electrical isolation switch. Place a bucket under the leak. Shut off the water supply if accessible. If pressure is above 2.5 bar, bleed a radiator to reduce pressure temporarily. Do not open the boiler cabinet. Take photos of the leak to show the technician.
Repair vs. Replacement
Pump seal and connection leaks are typically repairable. Heat exchanger leaks on boilers over 12 years old often signal replacement is the better decision. If your boiler is under 8 years old and the heat exchanger is under warranty, repair is the clear choice. A new condensing boiler will pay back through gas savings over its lifespan.