Question
To Marc Chapelle-Landscaping Architect- I thought I sent this to you but I guess I didn't from the person who answered it.Being an L.architect,I figured you'd know about this kind of stuff. I've lived in my home for 21 years.(It was a new home in a new neighborhood at the time). How do I know if my plat is correct? I started to mark out my property last summer to put up a fence and the new neighbor had a problem with it(property line)according to his plat. Before him that house was purchased by investors who had surveyors (or someone) there to mark the property. They had a metal detector and marked where the pin was. I keep wondering is the surveyors pin always correct or the plat? Do you know what the surveyors use or go off of to insure accuracy of their placements? (reference points) If surveyors have of difference of opinion this could go on forever that's why I was wondering. I don't know for sure which city office could help me with this but I wanted to know your opinion first.

Answer
Hello, Kat - This is the first time you've asked me this Q., but sadly not the first time I've answered other homeowner's about it.  Surveying is not just finding monuments and markers, but verifying the other guy's work, even from 20+ years ago.

The appropriate office would be the one that approves plats, parcel maps, and records of surveys in your county.  Each area has slightly different licensing and reviewing policies, but Land Surveyors have to be licensed in all 50 states, and go through rigorous training to get their LS licenses.  In some states civil engineers can also perform these duties, but it is becoming rarer for a PE (professional engineer) to do so.

To your question: Differences of surveying opinion do happen, but with modern surveying equipment it happens less often.  Errors are introduced in lots of ways, and can be compensated for by incremental adjustments, but rarely in feet, mostly in inches and 10ths of inches.  In the extreme, I have seen boundary line adjustments occur due to a house or driveway being built across property the other person didn't own, so it does happen, but both property owners need to work together to fix this sort of situation.

How big is your parcel?  If it is less than 1/4 acre, and in a subdivision, the likelihood of extreme error is remote.  Looking up the parcel is easy.  Verifying it is accurate requires a bit of digging into county records and maps.

I have worked on MANY residential parcels with poorly defined property lines and corners, and it is usually quite up-setting to the two land owners when I show them that yes, indeed, the neighbor's new tool shed, deck, fence, or water feature is actually on the neighbor's parcel.

How to verify your situation?  Contact a private. local, land surveyor.  The County Engineer may do it IF it is regarding a property line along the public's right-of-way for roads or utilities.  The local private surveyor can give you the clearest direction & estimated cost for verifying where the line actually is.  I had one done about two years ago for a client who wanted to put in a pool right to the property line, and the cost was about $800.  Just like any business, prices will vary based on area and demand.  

Look for a local surveyor that are licensed in your state as a "Professional Surveyor".  There are lots of them in the phone book, even in more remote communities - we have less than 6,000 population in our rural county and have 4 surveyors.

Good luck & happy new year ~Marc

PS - On a personal note, I was putting in a vegetable garden on my own property with a rototiller, and "accidentally" found one of my property corners with it -- Whammo! I had no idea it was so far into what I "thought" was my property.  It was in the right place and I was putting my garden in the public roadway easement unknowingly!!  So it can evne happen to the experts. ~M

ADDENDUM -- You may condiser looking for a surveyor (by state) here:
http://www.lsrp.com/proforg.html