My septic system periodically gets clogged with hardened grease build up which I have to manually clean out (about twice a year). I use a bacteria additive monthly and have the tank pumped bi-annually. The system is very old, but I don't believe the problem is anything other than this grease build up. I am wondering if grease traps are sold/installed in homes as they are in Restaurants and if that would help. Is there a non-commercial sized grease trap?

  • 1
    do you put a lot of grease down your drains? I've never heard of a tank needing to be pumped so often. Commented Dec 31, 2014 at 19:28
  • We don't know why there is so much grease collecting. The septic company says every other year is standard. But the cleaning out every 6 months is on the pipe leading into it, which is collecting the grease not in the tank.
    – Drai
    Commented Dec 31, 2014 at 19:50
  • Why is there grease in the drains in the first place?
    – DA01
    Commented Jan 1, 2015 at 0:00
  • We use every precaution against grease, but there is still hard white build up that stops the drain. It is before the waste reaches the tank. I assume it is from cooking grease/residue that does not get thrown out.
    – Drai
    Commented Jan 1, 2015 at 2:50

2 Answers 2


Don't dump grease down the drain. Discard it in the trash (or use it for further cooking.) Pour out grease/oil into a can for cooling, possible refrigeration and re-use, or to discard in trash. Wipe most remaining grease out of pots and pans on a paper towel and discard it, before washing.

Also, go with the recommendations of virtually every public health department and cooperative extension and stop wasting money on "bacteria additive" - none do any better than the ones in the waste stream naturally, and some have deleterious effects (they successfully "liquify wastes" and plug your drain field, when the whole point of the septic tank is to separate those solids so they can be pumped out.) A plugged drainfield is VERY expensive (you need a new drain field.)

You can install a small grease trap inside, but then you need to maintain it. Or you could install a large grease trap (pretty much like another septic tank) outside, ...but then you need to maintain it (in some places, there is a minimum pump schedule by law for grease traps.) Grease trap maintenance is decidedly gross - it smells terrible.





  • I don't dump grease down the drain. I can't find any references to "small grease traps" for non-commercial use. Do you know what I should be looking for?
    – Drai
    Commented Jan 1, 2015 at 2:51
  • grease trap or grease interceptor brings up plenty of google search results. a "14" or "20" lb capacity unit seems to be the most common small size, but this place does have an 8. shop.greasetrapsales.com/main.sc They are sold for commercial use as they are not a normal install for residences - as such "small commercial" is what there is.
    – Ecnerwal
    Commented Jan 1, 2015 at 4:30

I have a similar issue, but I do believe it may be due the fact that heavy duty detergent "creams" are used to cut heavy grease and fats from cooking vessels. The emulsion created then subsequently separates in the cooler ambient of the drain pipes resulting in adhesion to the PVC pipe walls causing periodic blockage.

Planning to design and install a serviceable 5 gallon bucket grease trap just outside the kitchen.

  • Curious-- how did your 5 gal bucket design work out? If it works well, please share your design or suggestions. I can't believe the prices they ask for these small grease traps $200-750 is what I am seeing. My kitchen sink drain feeds into my washer drain line. I continue to have block issues (upstream of where the washer connects to the system--so it has to be sink/dishwasher.)
    – peinal
    Commented Nov 27, 2020 at 14:53

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