We recently moved in to a 50 year old home that is on septic and uses forced air water boiler with baseboard heaters. Since we have moved in we have noticed a smell that I can only describe as acidic or tangy in the above ground basement. It is in the guest room closet (there are pipes running through the closet). The garage is on the other side of the wall that smells. Some days it is bad enough to make the whole house smell. Other days it just smells in that room. I haven't seen any signs of mold but I can't figure out what is making the smell. The house used to be on well water but is now on municipal water. I have two infants and want to make sure whatever the smell is that it won't effect their health. I have been told that an air quality inspection will cost above $550 which after buying a new house is a lot to spend if it turns out to be nothing dangerous. Any advice please? I am willing to try anything... this is really stressing me out. Thanks

May be a rotting rodent

If it were a rodent (which I know they've had in the past) how long would the smell last? It's been going on for 4 weeks now. Thanks.

About that long, until the body decomposes. I would contact a exterminator just to make sure if that smell could be from that