Septic Tank Inspection in Florida
If you are buying a home with a septic tank, you should consider having it inspected by a professional septic contractor. Our standard home inspection does not include this type of specialized, intrusive inspection. To properly inspect the septic tamk and system in Florida, the contractor will need to dig holes to access the underground parts of the system. This will include inspecting the tank, as well as the leach field.
Everything that goes down any of the drains in the house (toilets, showers, sinks, laundry machines) travels first to the septic tank. The septic tank is a large-volume, watertight tank which provides initial treatment of the household wastewater by intercepting solids and settleable organic matter before disposal of the wastewater (effluent) to the drain field.
FUNCTION OF THE SEPTIC TANK
While relatively simple in construction and operation, the septic tank provides a number of important functions through a complex interaction of physical and biological processes. The essential functions of the septic tank are to: receive all wastewater from the house separate solids from the wastewater flow cause reduction and decomposition of accumulated solids provide storage for the separated solids (sludge and scum) pass the clarified wastewater (effluent) out to the drain field for final treatment and disposal.
As stated, the main function of the septic tank is to remove solids from the wastewater and provide a clarified effluent for disposal to the drain field. The septic tank provides a relatively quiescent body of water where the wastewater is retained long enough to let the solids separate by both settling and flotation. This process is often called primary treatment and results in three products: scum, sludge, and effluent.
HOW LONG LIQUIDS MUST REMAIN IN TANK
Effective volume: The floating scum layer on top and the sludge layer on the bottom take up a certain amount of the total volume in the tank. The effective volume is the liquid volume in the clear space between the scum and sludge layers. This is where the active solids separation occurs as the wastewater sits in the tank.
In order to avoid frequent removal of accumulated solids, the septic tank is (hopefully) designed with ample volume so that sludge and scum can be stored in the tank for an extended period of time. A general design rule is that one-half to two-thirds of the tank volume is reserved for sludge and scum accumulation. A properly designed and used septic system should have the capacity to store solids for about five years or more. However, the rate of solids accumulation varies greatly from one household to another, and actual storage time can only be determined by routine septic tank inspections.
While fresh solids are continually added to the scum and sludge layers, anaerobic bacteria (bacteria that live without oxygen) consume the organic material in the solids. The by-products of this decomposition are soluble compounds, which are carried away in the liquid effluent, and various gases, which are vented out of the tank via the inlet pipe that ties into the house plumbing air vent system.
FLOW INTO AND OUT OF THE TANK
The inlet and outlet ports of the tank are generally equipped with devices such as baffles, concrete tees, or in more recent years, sanitary tees (T-shaped pipes with one short and one long leg).
THE EFFLUENT FILTER
In newer systems, there is often an effluent filter: one of the significant improvements in septic tank design in decades. They range from 4 to 18 inches in diameter. As we have described, the most serious problem with septic systems is the migration of solids, grease, or oil into the drain field, and the filter is effective in preventing this. A filter restricts and limits passage of suspended solids into the effluent. Solids in a filtered system's effluent discharge are significantly less than those produced in a non-screened system.
The septic tank also provides a buffering of flows between the house and the drain field. Large surges from the household, such as toilet flushing or washing machine drainage, are dampened by the septic tank so that the flows leaving the tank and entering the drain field are at substantially lower flow rates and extend over a longer period of time than the incoming surges.
It makes good sense to have the tank pumped at the time of this inspection. A professional septic contractor can perform both the inspection and pump the tank, killing two birds with one stone and assuring that you begin with an empty tank and a system that has been inspected. Often, you can negotiate with the seller to have them pay for the pumping.
It is recommended that you choose a home inspector who is a Certified Member of the American Society of Home Inspectors (ASHI), Registered Professional Inspector with the Florida Association of Building Inspectors (FABI), and ICC code certified as a Residential Combination Inspector.