The answer to 'septic tank no hot water' is that the issue is likely not related to the septic system, but rather a problem with the water heater or plumbing. A lack of hot water is usually caused by a malfunctioning water heater or an issue with the home's plumbing system, not the septic tank.
Some common causes could be a faulty thermostat, sediment buildup, or a problem with the heating element in the water heater. It's also possible there is a blockage or leak in the plumbing that is preventing hot water from reaching the taps. In most cases, this type of issue will require the expertise of a professional plumber to diagnose and repair.