Emptying Your Septic Tank

January 19, 2015 - Benjamin Dowson

Septic tanks are a smelly, but necessary part of a rural plumbing system. As we discussed previously here, septic tanks collect sewage from a home, separates the liquid from the solids, and discharges the effluent out into a septic field. But how is this discharged exactly? And what happens to the solid waste that is left behind? These are important questions homeowners with septic tanks should know the answers to in order to maintain a sanitary and properly maintained septic system.

When sewage is brought into the septic tank, it is naturally separated into solids and liquids. The solids sink to the bottom of the tank and the liquid (effluent) goes through a separation baffle into another container, where it is pumped out into a septic field.

Over time, the solids build up on the bottom of the septic tank and eventually have to be removed. This sludge should be removed every 2-3 years, and there are services that specialize in removing sludge from septic tanks. They come to your house in a big vacuum truck, stick a hose into your septic tank, and suck up all the sludge. We recommend that this be done in the springtime to give the bacteria culture in the tank time to grow before it gets too cold.

On the other side, there is the effluent which is discharged by one of two ways: either it is pumped out by a septic pump, or it is siphoned out. A septic pump works similarly to a sump pump. There is a float that detects the water level of the tank, and when it hits a certain level the pump automatically turns on and discharges the effluent to the septic field. The other way to empty the septic tank of effluent is for it to be siphoned out. This only works in certain cases, because it can only work if the septic field is lower than the tank; this method uses gravity to push the effluent into the septic field.

So here we have seen how both solids and liquids are taken care of in your septic tank. Liquids are pumped out or siphoned out, and solids are sucked out by a vacuum. Knowing these things is important for a homeowner because it will allow the homeowner to make better decisions regarding the proper care and maintenance of their septic tanks.