The answer to 'how to fix septic tank' is to regularly maintain and inspect your septic system. This includes pumping the septic tank every 3-5 years to remove accumulated sludge and scum, which can clog the system and cause backups or leaks. You should also have a professional inspect the entire septic system, including the drain field, to identify any issues or needed repairs.
If you notice signs of a problem, such as slow draining sinks, gurgling sounds, or sewage odors, it's important to address the issue quickly to prevent further damage. In some cases, you may need to have the septic tank pumped more frequently or have the drain field replaced if it has become clogged or damaged.