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Septic System Information

Home Inspector with Advanced Code Group

Some basic information about the process for determining the type of septic system.

The perc test results and the number of bedrooms will determine the square footage and height of the elevated sand mound unless you had a picture perfect perc test and are allowed a conventional "in ground" gravity fed system. Look around you at the other homes, if they are newer and they all have sand mounds it looks like you will too. For a 3 bedroom home a 900 gallon treatment tank is required and for a 4 bedroom you are up to a 1250 gallon tank. A 3 bedroom home will typically have a 1000 gallon tank and must be capable of handling 400 gallons of effluent a day, a 4 bedroom home will need to process 500 gallons.

There will be 2 tanks and a sand mound or "turkey mound" (if anyone knows where this term came from please let me know!) Your treatment tank must have 2 separate compartments and is where the liquids and solids are separated. From there, the liquid waste will go to the pumping tank or "dosing tank" where it is pumped under pressure to the elevated sand mound and perc through the gravel and sand layers the into the ground.

The dosing tank is usually the closest to the sand mound and it's lid is always at or above ground level. The treatment tank or "septic tank" is underground and should have a pipe sticking out of the ground where the waste first enters the tank. This is called the inlet inspection port to check the level of the tank. The main lid(s) to this tank are usually buried 98% of the time but must be within 12" of the surface.

It is very important that nothing be built on top of the tanks or sand mound. THE SAND MOUND MUST BE KEPT NEAT AND TRIM to keep any tree roots from infiltrating into the perforated piping and clogging the system. Keep grass growing and don't plant anything on it. There should always be a minimum of 12" of soil on top of the aggregate (gravel) which is on top of the sand layer.

I hope this has been informative enough. Thanks.

Jeff Remas