Many typical household cleaners are safe for your septic system, according to the U.S. Environmental Protection Agency. A septic system is full of living organisms that digest and treat waste. Its important to not overload the system with toxic chemicals like oil-based paints, solvents, pesticides or bleach. Any cleaner listed as "poisonous" should be used sparingly if it will end up down the drain and into your septic tank.
Laundry and Dishwasher Soap
Laundry and dishwasher soaps that are low-phosphorus or phosphorus-free are safe choices for your septic tank. Phosphate is a major water pollutant -- it acts like a fertiliser and can cause algal blooms to grow. Many states have set limits on how much phosphate can be put in soaps.
Large amounts of bleach may not be healthy for your septic tank, but leading maker Clorox stands by it's product as safe. When used as directed, Clorox Bleach is not harmful to septic systems, according to the company. "The bleach breaks down rapidly to mostly salt and water," according to the company's website. It would take 2 gallons of undiluted bleach to kill the helpful bacteria in a 1,000 gallon septic tank, according to Cornell University.
Disinfectants, like "pine cleaners" are safe for septic systems under ordinary circumstances, such as emptying a bucket of mop water down the drain. It would take 5 gallons of pine cleaner, straight from the bottle, to kill the helpful bacteria in a 1,000 gallon septic tank.