There are many items that can cause problems with septic tanks by clogging effluent filters, pipes, drain lines, and pumps, leading to expensive maintenance.
Fibrous items such as:
Disposable diapers – these are another clogging hazard and cause huge problems with septic tanks as they are not biodegradable. Non-biodegradable materials in your tank will stay in your system and remain a potential hazard until your tank is pumped.
Pool and spa products – Most pool and spa products are formulated to kill bacteria, often by using high levels of chlorine. Since your septic system relies on healthy bacteria for proper treatment, we recommend against putting any pool or spa products into your system.
Garden chemicals – Pesticides, herbicides, fertilisers, and other toxic chemicals are harmful to septic tank biology and can remain harmful beyond the drainfield.
Recreational vehicle (RV) holding tank contents – deodorants and stabilisers in RV holding tanks are very harmful to septic system biology. Even when labelled "biodegradable," these products often biodegrade into other harmful chemicals that can damage the biology in your system.
Rain gutters, storm drains and hot-tub water – Don't allow surface water to drain into your wastewater system or ever connect storm drains or rain gutters. Also, hot-tub water shouldn't be discharged into it either. Adding this extra water will increase your costs, reduce the systems capacity as well as flood the drainfield. Finally, excess solids can be washed through the tank, causing problems with septic tanks.