Undisclosed storm shelter

[Thomas McClintick]

Well I bought my first home which has a deck spanning the back of the house. While updating the deck I noticed a storm swelled under the deck. It was not in any of the paperwork and from my understanding this is something that has to be disclosed. Under closer look  it looks to be holding water... So I do under the home and see the the piller are sinking badly in some spots. Why my inspector did not note any of this I do not know.  But my question is is the seller of the home  in the wrong herelegally for not disclosing the storm shelter of am I stuck to deal with this all my self