Bosch water heater leaks water from the bottom of the unit

Safety first: Turn OFF power and close the cold water inlet valve immediately. If gas-fired, also close the gas shutoff valve. Water and electricity together are hazardous.

• Identify leak source: Remove the front cover and use a flashlight to locate the exact origin of the leak. Look at the heat exchanger, water manifold, and connections.
• Tighten fittings: Gently tighten any accessible threaded or compression fittings that are seeping. Do not overtighten plastic fittings.
• Replace O-rings: If leaks are at manifold joints, replace the O-rings or gaskets with Bosch-approved parts.
• Freeze damage: Look for split copper tubes or deformed components. Freeze-damaged heat exchangers typically require replacement.
• Heat exchanger leak: If water is seeping from the heat exchanger body, the exchanger must be replaced; this is generally a professional repair and may justify replacement of the unit depending on age.