Yes, bleach has great anti-septic properties. Which is why we use it. To kill germs and bacteria. Remember this, anything that is anti-septic will harm your septic system. It’s okay to use in extreme moderations. If you use too much you can kill the contents of your septic system. Instead of pumping every 3-6 years you could be pumping every 3-6 months. If that bacteria in your tank dies due to bleach it will be obvious to me.