Do I need a real estate attorney?

To answer your question, I would recommend you either hire a real estate or construction attorney that is familiar wtih DEP and these types of issues. When going against a government agency, it is not the best thing to do pro se. What you are trying to do is place liability on the previous owner, but to do so you will have to prove they are the one who filled in the wetland. The other item you need to verify is what you sales contract stated. Was there a disclosure clause asking the seller whether they were aware of any issues with the lot. Lastly, one big hurdle I see you will have to overcome is when you build a home, there are several surveys that must be done. In either case these surveys should have shown the wetland areas. I can tell you since the work is done, DEP is less likely to work with you but try to negotiate with them. But as stated before, if the law suit is pending, I recommend you hire an attorney.

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Mr. Phillips is absolutely correct in his response to you. Your options are to hire an attorney, ask for attorney fees to be reimbursed from the defendant. You should file a suit against all involved, the surveyor should have disclosed this property as wetlands, the appraiser would have access to these records as well, the former owner for non disclosure, the realtor and broker agency for non disclosurer, the former builder of the property is need be. Run to your nearest real estate litigation attorney.