Possibly that small amount or infrequent washing also recommended online have worked in your favor. Septic Safe Laundry Detergent list is here. The 7 Best Detergents For Septic Systems In 2021 Best Laundry Detergent Septic System Safe Laundry Detergent This list is latest in 2021. Best laundry detergent for septic systems . After doing some research with septic system companies including Wind River Environmental these are the best detergents for septic systems. Bear in mind that septic tank safe laundry products are usually more expensive than regular detergents. Magnesium Sulfate Epsom Salts. Inexpensive powdered detergents may contain excessive amounts of filler or carrier. However you can always turn to DIY options that are cheaper and safer for your septic system. Find out about 12 of the best laundry detergents for your septic system. Most dry detergents contain montmorillonite clay as the primary filler. Septic tank safe detergent should have low levels of s...