For a Seattle Street Improvement Permit (SIP) survey, the required topographic coverage includes the full width of adjacent rights of way, at least 10 feet beyond the right of way into the private parcel being improved, and at least 50 linear feet along the right of way beyond the project site and/or proposed work. Those are SDOT’s published minimums. The survey may need to reach farther where the proposed improvement meets existing grades or infrastructure.
Plot SDOT’s minimum survey limits
Plot the site and proposed work on a plan before setting the field limit. For a project adjacent to an intersection, SDOT requires the entire intersection, including all four corners, to 20 feet beyond the far point of tangency of each curb return or roadway edge. If an adjacent street lacks curb and sidewalk, the SIP Project Manager may request coverage of the entire block. Improvements in an unopened or unimproved alley require survey coverage to the intersecting streets. Check the current guide and project checklist with the SIP team when defining the scope.
The topographic survey and the finished base map can have different limits. SDOT allows the base map to cover less area, but it still must show existing infrastructure affected by right-of-way construction.
Then test the edge against the proposed work
Suppose a new sidewalk must meet an existing driveway just beyond the planned field limit. The driveway grades may determine whether the transition works. If the survey stops before the driveway, the designer may lack the elevations needed to resolve the transition. The civil designer should mark the tie-in and the grades needed; the surveyor can then confirm the additional coverage and access.
Use the same check for curb ramps, drainage structures and utility connections. Show the required SDOT area and any design-driven additions on one marked survey request. Label areas that cannot be accessed and distinguish visible surface features from utility information supplied by records. Terrane’s SIP survey-base guide covers the control and drawing handoff once that field area is defined.
