The answer to 'septic tank no hot water' is that a septic tank issue is unlikely to be the cause of no hot water in your home. The septic tank and the hot water heater are separate systems, so problems with one generally do not affect the other. Common causes for no hot water are a malfunctioning water heater, a broken thermostat, sediment buildup, or a leak in the plumbing.
If you're experiencing no hot water, you'll want to first check the water heater itself. Make sure the pilot light is lit and the thermostat is set to the proper temperature. You can also try flushing the tank to remove any sediment buildup. If those basic troubleshooting steps don't resolve the issue, it's best to call a professional plumber to diagnose and repair the problem.