Septic here too. I've only had a minor problem 2 times. Both times Dh was cleaning something, and made a strong chlorine solution using chlorine tablets, and water. He poured the remainder down the drain. The first time, I didn't realize what he'd done. The second time it dawned on me what he had done. When I asked him about it, he said he did it, and couldn't understand why I was so upset. When he got inside, and saw the mess from it backing up into the bathtub, and showers, he knew why I was upset. I realize he's had city water, and sewage since he left his mother's home, but dang, for a guy that grew up with a septic system, you'd think he's know more.