removing vomit odor from carpet::There are 9 other families all with their own park models removing vomit odor from carpet

removing vomit odor from carpet::There are 9 other families all with their own park models.
The smell has been lingering inside for 3 summers now.
And there is no animal to be found anywhere!
All carpet has been ripped out and replaced with linoleum and wood flooring.
I just about lost my dinner when i walked in the place tonight!
The smell is unbearable.
They have tried baking soda, very expensive air filter systems, they always leave the windows cracked when they leave for the week, and all windows and doors wide open thursdaysunday.
Could this be coming from the water heater and pipes?
Or what in the world could it be?
If anyone has any ideas how we can get rid of this odor once and for all we will all be forever grateful!
Oh yeah, all ten park models have the same water source, but only one has the odor.
removing vomit odor from carpet::