Contact the architect or builder. To find this information, check any paperwork you signed or received when you bought your house, such as the deed or mortgage paperwork.
Contact the real estate agent or agency you worked with when you bought your house. The agency may have blueprints on file, especially if the house is relatively new, or it may know where to find them.
Search the public records databases some states keep online. Even if you don't find your blueprints, you may find leads on where to look for them.
Go to your city or county building department, where building permits are kept. Sometimes blueprints are filed with building records. Home builders must file permits and other paperwork, which could have the architect's or builder's name on them.
Ask if your local library keeps architectural records. If your home was built before 1950 or has historical value, the library may have blueprints in its archives.
Call your home inspector, electrician or anyone else who is familiar with your home's structure. They might keep blueprints in their records.
Ask the previous owners. They may have a copy of the blueprints.