Newly bought house is having serious structural issues which the sellers claimed to not have in their full disclosure statements.

Purchased a house in Seattle, WA on 2/11/2016. Under the full disclosure statements signed by the sellers as part of the paperwork for the sale, the sellers checked NO on the box asking "has the basement flooded or leaked". In the first week after moving in, water started leaking from the a section of the basement wall. A professional inspector was brought in to access the situation, and he concluded that this has been a long standing issues and there is evidence of unsuccessful attempts to repair the damage. Currently, our family is plotting to contact the previous owners to tell them that we will invoice them for the full cost of the repair on the leaks. If the sellers refuse to cover the invoice, then we want to pursue legal action. Please share your thoughts on this situation and suggests ways to handle this.