The answer to 'why is my water heater burst pipe' is that a burst pipe on a water heater is often caused by excessive pressure buildup or corrosion. This can happen when the pressure relief valve fails, the tank rusts through, or the heater is set to an excessively high temperature. Symptoms include leaking water, decreased water pressure, and potentially water damage around the heater.
In many cases, a burst pipe on a water heater will require professional repair or replacement. Attempting to DIY the repair can be dangerous if you're not experienced with plumbing work. It's best to call a licensed plumber who can properly diagnose the issue, replace the damaged pipes, and ensure the water heater is functioning safely.