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Pumping and Inspecting Your System


What to expect

Annual inspections of your septic system are recommended to ensure that it is working properly and to determine when the septic tank should be pumped. By inspecting and pumping your system regularly, you can prevent the high cost of septic system failure.

Inspecting Your System:

Although a relatively simple inspection can determine whether or not your septic tank needs to be pumped, you should consider calling your local health department or hiring a professional contractor. A professional can do a thorough inspection of the entire system and check for cracked pipes and the condition of the tees or baffles and other parts of the system.

A thorough septic system inspection will include the following steps:

  1. Locating the system: Even a professional may have trouble locating your system if the access to your tank is buried. One way to start looking is to go in your basement and determine the direction the sewer pipe goes out through the wall. Then start probing the soil with a thin metal rod 10 to 15 feet from the foundation. Once your system is found, be sure to keep a map of it on hand to save time on future service visits.
  2. Uncovering the manhole and inspection ports: This may entail some digging in your yard. If they are buried, try to make access to the ports easier for future inspections. Install risers (elevated access covers) if necessary.
  3. Flushing the toilets: This is done to determine if the plumbing going to the system is working correctly.
  4. Measuring the scum and sludge layers: There are two frequently used methods for measuring the sludge and scum layers inside your tank. The contractor may use a hollow clear plastic tube that is pushed through the different layers to the bottom of the tank. When brought back up, the tube retains a sample showing a cross section of the inside of the tank.

    The layers can also be measured using a long stick. To measure the scum layer using a stick, a three-inch piece of wood is attached across the end of the stick to form a “foot,” and the stick is pushed down through the scum to the liquid layer. When the stick is moved up, the foot meets resistance on the bottom of the scum layer, and the contractor marks the stick at the top of the layer to measure the total thickness. As a general guideline, if the scum layer is within three inches of the bottom of the inlet baffle, the tank should be pumped.

    The sludge layer is measured by wrapping cloth around the bottom of the slick and lowering it to the bottom of the tank. This should be done either through a hole in the scum layer or through the baffle or tee, If possible, to avoid getting scum on the cloth. The sludge depth can be estimated by the length of sludge sticking to the cloth. If the sludge depth is equal to one third or more of the liquid depth, the tank should be pumped. 
  5. Check the tank and the drainfield: The contractor will check the condition of the baffles or tees, the walls of the tank for cracks, and the drainfield for any signs of failure. If your system Includes a distribution box, or pump, the contractor will check these too.
  6. Clean your effluent filter - If your septic tank has a filter, it should be pulled out and cleaned of any debris that may be deposited on the screen. Most screens are designed to be pulled from the inspection port above the baffle on the drainfield side of the septic tank. The filter can be hosed off.


When To Pump

How often your tank needs to be pumped depends on the tank size, the number of people living in your home, and the habits of your particular household. Garbage disposal and high-water-use technologies, such as a hot tub or whirlpool, also affect the pumping frequency.

To estimate how often you should have your tank pumped, refer to the table below. This information combined with observations from annual inspections will help you to estimate your individual pumping schedule.

When it is time to pump out your tank, be sure to hire a licensed contractor who has the appropriate equipment and can dispose of the sludge at an approved treatment site. You can find listings for licensed pumpers and haulers in the yellow pages, or contact your local health department for assistance.

It’s a good idea to be present when your tank is being pumped. Make sure the contractor uses the manhole, not the inspection ports, to pump the tank to avoid damaging the baffles or tees. Also make sure all of the material in the tank is removed, It is not necessary to leave anything in the tank to “restart the biological process, but it is also not necessary to scrub or disinfect the tank.



Tank Size (Gallons) Household Size (number of people)
  1 2 3 4 5 6
  Estimated septic tank pumping frequencies In years
500 5.8 2.6 1.5 1.0 0.7 0.4
750 9.1 4.2 2.6 1.8 1.3 1.0
900 11.0 5.2 3.3 2.3 1.7 1.3
1000 12.4 5.9 3.7 2.6 2.0 1.5
1250 15.6 7.5 4.8 3.4 2.6 2.0
1500 18.9 9.1 5.9 4.2 3.3 2.6
1750 22.1 10.7 6.9 5.0 3.9 3.1
2000 25.4 12.4 8.0 5.9 4.5 3.7
2250 28.6 14.0 9.1 6.7 5.2 4.2
2500 31.9 15.6 10.2 7.5 5.9 4.8
Estimated septic tank pumping frequencies In years.  These figures assume there is no garbage disposal unit In use.  (Source: Pennsylvania State University Cooperative Extension Service).

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