How Much Does It Cost to Pump a Septic Tank? | Angie's List
When wastewater enters your septic tank, it naturally divides into three parts: Solids sink to the bottom and form a sludge layer.. Liquids stay in the middle and form a layer of mostly water.. Oils and fat rise to the top and form a scum layer.. The liquid layer accounts for 90 percent of your tank's capacity, meaning excess water use can affect the tank's performance over time.