Re: Neighbor's Treehouse on Our Property
Mountain property. Resort area. Smallish lots. Sounds like big Bear.
The lots around Big Bear, like many other mountain resort areas in CA are parts of subdivisions reflected on filed maps. If that is the case, just because you don't see the lot corner monuments doesn't mean they don't exist. They may be in the brush or even a bit below the ground surface.
The cost you were quoted, $750, seems a bit low but not really out of line if the surveyor is familiar with your subdivision, is aware that much of the monumentation remains in place, has experience that the monumentation within this subdivision (or at least in other subdivisions performed by the same original surveyor) tend to agree well with dimensions shown on the subdivision map, and has an office located fairly close to the site (minimal travel time).
If any of those conditions is not true, then a reasonable cost could go up pretty drastically. At $750, your surveyor is probably not planning on filing any maps, or perhaps a Corner Record at the most. If a Record of Survey is required, the County map review fee alone may easily exceed $750, and $750 almost certainly wouldn't cover the surveyor's efforts to complete the survey, prepare and submit a Record of Survey. I don't practice in SB Co., but I understand that their map review fees are notoriously high, sometimes exceeding the fee that the surveyor charged his client to perform the survey and prepare the map. The county where I had my private practice charges $135.
There are five conditions that, when encountered in the course of a survey, make filing a Record of Survey mandatory under State law. Sometimes the requirement is pretty straightforward, and sometimes it is a matter of professional judgment as to whether the circumstance (such as a material discrepancy between record dimensions and dimensions actually measured).
In your situation, you are concerned about a structure belonging to a neighbor possibly being in part or in whole on your property. Even if a Record of Survey is not required under State law, you want some manner of map that will show where that tree house is relative to your property boundary. Make sure that the surveyor you've already spoken with and any others you may speak with understand that. I doubt that the $750 fee includes such a map.
If your property is not part of a subdivision, if monumentation truly is nonexistent on your lot and/or relatively close by, if there are obstructions on your property and/or other locations from which a surveyor would need to measure in order to establish your lines, if a Record of Survey map is required, a reasonable fee could easily reach four or five times what you were told.
As to how you described roughly determining where your property lines are, you are on way too thin a basis to assert that a structure which may be near a line is encroaching. If your lots are both part of a subdivision, it is most likely that the dimensions shown on the Assessor's Parcel Map were taken directly from the filed surveyor's subdivision map, and so are likely fairly reliable.
BUT those dimensions are likely incomplete, and you did not describe that you measured from a nearby precise point that has any direct and precise relationship to the lot lines. You stated that you measured from your neighbors' lots. Well your lot is 110' wide, and I expect that your neighbors' lots are at least 50' wide. so from what point on or in these lots did you measure. You said something about a line that seemed to be locally accepted as a lot line. That's very dangerous ground (no pun intended) that most surveyors are afraid to include in their opinion. Any measurements made that are not made in reference to the original monuments of the survey are essentially worthless at best and can be very misleading at worst.
If you are going to make any assertions about encroachments, you need a survey performed by a licensed surveyor.
If the treehouse was not represented to you as being part of the real estate purchase, then it is not yours, regardless of whether it is found to be on your lot or not. If it is found to be on your lot, you can ask (or demand if necessary) that your neighbor remove it. whether it is considered to be personal property or part of the real property is a little foggy with a treehouse. The tree is clearly part of real property under CA law. The treehouse, being permanently affixed to the tree, which has it's roots in the ground would seem to me to be part of the real property, but I don't know.
What I do know is that if you have no basis, beyond the belief that it may be on your lot, that it is yours (no understanding of having bought it with the lot, as that understanding was when you made the purchase), then it is not yours and you cannot legally just take it over or dismantle it. If it is found to be on your lot, you may be able to dismantle it after giving your neighbor (the rightful owner of the treehouse) ample opportunity to remove it, but there are steps you will need to take before then. Since this thing sounds almost like a cabin in a tree as opposed to a kid's fort made of remnant lumber, it probably has substantial value and you will need to seek legal counsel before removal.
There are also steps you can take to prevent the treehouse's existence from ripening into the basis for a prescriptive easement. Ask your attorney about how to do that per Civil Code ß813, and any additional steps you should take. You can probably, under that and other code sections, grant revocable permissive use should any portion of the treehouse be later found to be on your lot. That way, you put your neighbor on notice that you believe that it probably is at least part on your lot, reserving the right to ask them to remove it at such time that you are able to definitively ascertain it's relationship to the lot line by survey.
Until you have a survey, you have no real basis to assert ownership of the ground below it in insisting that they remove it. If it is a privacy issue, you may have grounds along those lines, but that's well out of my area of expertise, so again, get advice from a local attorney on that score.
I wish you success in getting the matter resolved.
I'm a surveyor, not your surveyor & not an attorney.
Advice is general survey, not legal. Hire a local professional for specific advice.