How to properly wash your septic tank filter

In an ideal scenario, only wastewater from the tank should drain into the drain field. But it is possible for the wastewater to carry other unwanted waste like hair, solid waste, and grit into the drain field. When such debris gets into the leach field, it causes blockages and pollution. This underscores the importance of a septic tank filter. The septic tank filter is typically located in the baffle of the septic tank and it helps to filter out any suspended solids from the wastewater before it goes into the drain field. Just like your septic system in general, the septic tank filter also needs regular maintenance. Failure to clean the filter regularly can result in serious clogging and other related problems. Even though the septic tank filter can function for years without the need for replacement, it is a good idea to inspect twice a year (before and after winter) just to be sure it is ok.  As a bare minimum, the filter should be cleaned every time the tank is pumped.

cleaning filter septic tank

Steps to follow when cleaning the septic tank filter

Before you start cleaning the filter, make sure you have dressed in full-length pants and shirt, safety goggles, gloves, and boots.  You can then go ahead and clean the filter by following these steps;

  1. Start by removing the access lid to the septic tank. this shouldn’t be too complicated if the access lid is above ground. If it is buried, you might have to locate it first. Here is a link to an article that explains exactly how you can locate your septic tank.
  2. Once you have removed the access lid, you can go ahead and remove the filter cartridge. Make sure to hold the filter over the first manhole (because this is where the organic waste is treated) so that any effluent from the filter will run back into the septic tank. If you drain it in the wrong manhole, untreated wastewater might go into the drain field.
  3. While still holding the cartridge over the open port of the septic tank, spray the cartridge with a water hose in order to remove any material that may be sticking on it.
  4. Some of the filters have an alarm that activates when the filter is need of cleaning. If you have such a filter, check to ensure it is working properly. You can do this by lifting the float switch to sound the alarm.
  5. Inspect the modulating orifices and the vent hole to ensure there is no debris stuck in there. If you find any debris, spray it away with the hose
  6. Replace the cartridge by placing it firmly into the saddle holes and then clean any spillages around the area.
  7. Close the septic tank lid
  8. Change your clothes right away and then wash and sanitize your hands.

TIP: record the date of inspection and any other important notes in a maintenance book/file which you can refer to in the future.

Keeping the septic tank clean

When you keep the septic tank clean, you will have fewer problems with the septic tank filter. The first rule in keeping the septic tank clean is watching what you send down the drain. Any products that are not biodegradable should be thrown in the trash and not flushed in the toilet. That includes products that are often mistaken for biodegradable like baby wipes, cotton buds, cigarette butts, etc. This also applies to chemicals and other toxic substances.

It is also important to stick to the recommended septic tank pumping schedule. How often you are required to pump the tank will depend on your jurisdiction. Do not assume that you can skip the pumping just because the septic tank doesn’t show any signs that it is full. It is always better to be safe than to be sorry.

Using biological additives can also help to keep the septic tank clean. When you add these additives into the tank, they introduce billions of bacteria into the system. These bacteria will help in the digestion of organic waste in the septic tank. The septic tank typically has bacteria added every time you flush the toilet but since the average home uses substances that can harm the bacteria, it is beneficial to replenish the bacteria every now and then by adding biological additives. This will help to keep the septic tank and by extension the septic tank filter clean.


As a rule of thumb, you should always clean the septic tank filter when doing your routine pumping. But since this will typically be after a couple of years, you should inspect the filter twice a year – just before winter and right after winter. It is best to use a filter that has an alarm. This alarm is programmed to go off whenever the filter is need of cleaning. If you clean the filter regularly and take good care of it, it should serve you for years without any issues.


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