We built a new home in 2006, with a ceramic farmer's sink and a double drawer dishwasher. There is an AAV vent under the sink cabinet, since it is an island sink. Ever since then, we've had this smell of dirt/mud and mold growing inside the cabinets. Several plumbers have come out, cut out the cabinet bottom (we've on a slab), had the leak detection folks out, and about all we've come up with is an extra open pipe under the cabinet that had no purpose, and was sealed up with foam spray by the plumber. The odor also comes up through the kitchen drain whenever you turn on the disposal (had done tried running bleach, vinegar, and various cleaners down the drain to no avail). Next on the list is to try a gas leak test (expensive, so have held off). The 2-10 warranty folks will fix whatever it is, but it's up to us to find the cause. The homeowner's insurance won't touch is because the builder originally started the process of attempting to finding out what the problem was.

Does anyone have any ideas on this one?? I'm wondering if having a two drawer dishwasher and one AAV vent is the problem?

Perhaps it's coming from where the pipes penetrate the slab, instead of from the pipes... good luck.

OK here is what really catch my attention "The 2-10 warranty folks will fix whatever it is, but it's up to us to find the cause. The homeowner's insurance won't touch is because the builder originally started the process of attempting to finding out what the problem was.
" The insurance companies that do home warranty are not your friend and will try everything to make it difficult to access their wallet. It matters not one red cent who looked into the problem, you or your contractor, the insurance folks can not deny your claim based on this. An AAV can fail so this may be a cure but good plumbers can make looped drain for an island that doesn't require an AAV. I'd get really crabby and start asking the guy at the insurance company who his boss is.