A property line change involves moving the property boundary between your property and the property next to yours. Most often, our customers want to move the property line of a single-family house.
You may want to move your property line to:
You cannot create a new lot by moving your property line.
You need a lot boundary adjustment to move your property line, or to create a new lot.
You need to show us that moving your property line will still maintain lots which conform to our land use rules in the Seattle Municipal Code (SMC) and our building codes.
If your property is in a single-family zone (SF5000, SF7200, or SF9600), you need to follow the rules below. For complete requirements, consult the land use code (SMC 23.44). If your lot is in another land use zone, we may have different rules for you to follow; consult our land use code or ask our land use planners.
Minimum lot size. Your single-family lot must be at least 5,000, 7,200, or 9,600 square feet depending on which single-family zone your house is in.
Minimum yards. Your single-family house can’t be too close to the property line in your front, side, and rear yards. Most often, we require your house to be 20 feet from the front property line, 5 feet from the side property line, and 25 feet from the back property line (or 10 percent of the lot depth if it is less than 25 feet).
Parking and access. Your single-family lot must meet our rules for parking and car access to your property. Usually, we require you to maintain the property’s parking spaces and access to them. At a minimum, we require one parking space per lot.
Regulations that govern environmentally critical areas. If your single-family lot is in an environmentally critical area, you must have a survey that delineates the area on a drawing when you apply for a lot boundary adjustment. We may have other requirements.
Utility service. Your single-family lot must meet our minimum levels of service for water, sewer, power, and fire access.
Fire separation between buildings. If you’re moving your property line, the line’s new location should be at least 5 feet from your single-family home, garage, and related buildings. In most cases, your buildings’ walls and eaves must be fire rated if they are less than 5 feet from your property line’s new location.
A licensed surveyor usually creates the documents for your lot boundary adjustment application. In some cases, you may create them if you can develop scaled drawings with lot lines, bearings, right-of-way information, building and lot line dimensions, and location of all utility services and trees.