Smell of gas near the water heater, especially when it is operating.

Critical safety warning: Immediately turn off the gas supply at the main isolation valve. Do not use naked flames or operate electrical switches near the appliance. Ventilate the area by opening windows.

• Do not attempt DIY gas repairs: Gas leaks must be located and repaired by a licensed gas engineer.
• Evacuate if strong smell: If the smell is strong or widespread, evacuate the building and contact emergency gas services.
• Professional leak test: A technician will perform a tightness test and use leak detection fluid on all joints, including the gas valve and burner manifold.