Your questions help me to realize I didn't give enough info,
I don't have any fish tanks
The smell is there even when the fridge is moved out.
It is still there after trash was taken out, and the trash compactor is at one end of the counters (near the door) and the fridge is at the other end.
There is a walk around porch for the side to the back and there are no plants near that area.
They only get the moodlet when they are near the grid square where the fridge sits.
I took out the floor in the whole kitchen and the nursery two rows over on that side of the wall, took out the wall. Replaced them and when I had them walk in that area, I still get the moodlet.
House is on a foundation, I will have to learn how to make a pool with a house on foundation.
I will try hiring a maid; I have a Boney and she ignores it, it seems as if only the family members are affected by it.
My family has the heir and they are married, so they can move to the next town.
I think I will move them and then go back to the town in a save and tear the house apart, leaving a large section open in that area and see what I can find. Move a sim there and see if they get the negative moodlet from just walking on the tiles.
Build a pool in that area and see if I can find what the problem is.
Frustrating, I had done some changes to the house that I think improved it. I wonder if I could move the house and see if the dirty moodlet pops back up in the new location.