Plan Check Comment: Land Surveyor

[David B.]

I recently submitted plans for a backyard ADU and a kitchen extension project. The city reviewed the plans and came back asking for this:

Please provide verification from a Civil engineer, a Land surveyor or any other legal documents to show actual location of the property line.

From my understanding, they want something official to use as guidelines for setbacks since the ADU is close to the existing fence. The city wants to use offical property lines for the setback guidance instead of just where the fence is. Does anyone have experience or a referral for someone they've used for the same request? Could something else besides an expensive land survey ($3k is the quote I got so far) be used to satisfy the request?