A real estate contract washington is, at its core, a legally binding agreement made between two or more parties in a Washington real estate deal. Ensure you know the legal requirements and disclosures of a Washington real estate purchase agreement.Fill in our template to create your agreement. Many of the steps in purchasing a new construction home are similar to purchasing a resale, such as signing a contract and securing a loan. Today I wanted to take it back to the beginning and discuss the residential purchases sale agreement now here in Washington State. A new construction purchase and sale agreement or sales contract is similar to a resale contract but applies to a newly built home. Description of The Property. There are some more nuanced items you should be sure to include in your real estate purchase contract, including the financing terms and closing date.