Septic Tank Outlet Filter Installation

I've mentioned several times in other threads that I installed a filter between my septic tank and drain field. I thought I'd follow up with more info.

I initially installed a strainer on the outlet of our clothes washer after reading that the synthetic fibers from clothes could clog a septic drain field. I did this in hopes of getting some more years our of our existing 30 year old septic system system. Although the strainer I installed was a fairly large marine-grade strainer I found we were having to clean it out more often than we liked.

I decided to install a filter in the septic tank that would capture this junk before it ended up in our septic field. I called our local septic guy and had the system pumped out with the intent of crawling into the tank (if needed) and cutting off the outlet tee and installing the filter myself after he was done. When I told him what I was up to he volunteered to cut the old outlet tee off for me so I could install the filter. I agreed of course and he earned a $20 tip by doing it. I was then able to install the outlet filter from above ground. The photo below shows the outlet pipe to the field after the tee was cut off. The old tee along with the riser and access port is also shown on the ground in the 2nd photo.

I clean it twice yearly with a hose. I installed a short section of PVC pipe on the filter that allows me to pull it out easily once the cover is removed. You just wash it off with a hose. A floating ball valve is built into the filter assembly that shuts off flow to the field when the filter is removed. So far, so good. Only time will tell if it was worth the expense/effort

Photos of the installed filter assembly and removed filter cartridge below.

zrock said:

If your outlet is set up properly their should be little to nothing to clean off as the bottom pipe should always be a few feet below the outlet so it should never get anything but fluids.

Click to expand...

I can visualize how a strainer could be inserted into the vertical portion of the outlet tee. I'm not sure I'd want to mess with removing it for cleaning though. With what I've installed all I have to touch is the PVC pipe that's attached to the filter cartridge.

I think that one of the issues with the plastic fibers is that their density is so close to that of water that they stay suspended rather than sinking or floating which is why they end up in the drain field.