So I was called to a gas station to clean a kitchen sink drain, come to find out that there's a grease trap, so I told the owner to get it pumped out, he does, but said his sink don't drain still, so I go back over take the lid off the grease trap and sure enough its full of water, and the way it looks it should work like all the other ones I've seen, in 1 side and out there other, but this 1 coes in, but on the outlet side there's a whole but it just goes up to a clean, and this is a in ground trap, I was thinking that there should be a t or like a y there for cleaning it out but I don't know, so if I'm missing something here then please let me know, thanks any idea is apperciated, curtis