To fix a leaking hot water system, follow these steps or read this article:

1. Turn off power and water supply: Switch off the electricity or gas supply to the heater and close the cold water valve to prevent further leaking.

2. Identify the source: Check for leaks around the pressure relief valve, tank, pipes, or fittings. A leak from the tank may indicate corrosion or damage.

3. Replace faulty parts: If the pressure relief valve or pipes are leaking, you may need to replace them. Use plumber's tape to secure new fittings.

4. Check the temperature: If the water temperature is set too high, it can increase pressure and cause leaks. Adjust it to a safe level (usually around 120°F/49°C).

5. Call a professional: If the leak is severe or from the tank itself, contact a plumber or technician for repairs or replacement of the unit.