A mortgage survey is a simplified drawing, prepared for a lender, that shows where a house and other improvements sit on a lot. It looks similar to a boundary survey, and the two are often stored together in closing papers, but it is a different product with a narrower purpose. Mixing them up can lead to a fence in the wrong place or a permit drawing that reviewers won’t accept.
Quick answer: A mortgage survey (also called a location survey, house location drawing or mortgage inspection plan in some states) shows improvements on a lot so a lender can spot obvious encroachments. It usually does not set corner markers and may say it must not be used for building. A boundary survey establishes the legal property lines and corners and can be relied on for construction.
What is a mortgage survey?
When a home is bought or refinanced, some lenders and title companies in some states want reassurance that the house is on the lot it should be on and that nothing obviously crosses a line. A mortgage survey provides that at a lower level of detail than a full boundary survey. It typically shows the lot outline from records, the house and major improvements, and approximate distances to the lines. Names and rules vary by state, and some states no longer use this type of survey at all.
What is a boundary survey?
A boundary survey is a full professional determination of a property’s legal boundaries. The surveyor researches records, measures in the field, recovers or sets corner monuments and certifies the result with a seal. It is the survey to rely on for building near a line, fences on the boundary and disputes. Our guide to the types of land surveys places it among the other survey types.
Mortgage survey vs boundary survey compared
| Mortgage / location survey | Boundary survey | |
|---|---|---|
| Purpose | Reassure a lender or title company | Establish legal lines and corners |
| Corner markers set | Usually no | Yes, found or set |
| Precision | Lower | High |
| Typical note | “Not to be used for fence or building construction” | Surveyor’s certification and seal |
| Use for building on the line | No | Yes |
| Use as a source for a site plan | Often, with care | Yes, the best source |
Why the “not for construction” note matters
Many mortgage surveys carry a warning that they must not be used to establish lines for fences, additions or other improvements. That note means exactly what it says: the surveyor has not verified the boundary to the standard needed for building. If you build a fence on a line taken from a mortgage survey and it turns out to be on your neighbour’s land, the drawing will not protect you.
Can a mortgage survey be used for a building permit?
Sometimes, indirectly. Many permit offices accept a site plan drawn from the best available records, and a mortgage survey can be one of those records when the project is comfortably inside the setbacks. It is not a substitute when:
- The permit office asks specifically for a boundary survey.
- The project sits at or near the minimum setback.
- The drawing’s note prohibits use for construction and the reviewer enforces it.
- The lot has changed since the mortgage survey was drawn.
For how the documents fit together in a permit application, see our pillar guide on site plan vs survey.
Which one do you have?
Look for these clues on the drawing:
- Bearings and monuments (for example, “iron rod found” at corners) suggest a boundary survey.
- Titles such as “mortgage inspection”, “location survey” or “house location” suggest the simpler product.
- A certification addressed only to a lender and title company, rather than to you, is typical of a mortgage survey.
- A “not for construction” disclaimer is a strong sign it is not a boundary survey.
Our guide on using an old survey for a permit covers what reviewers look for in older documents.
When a mortgage survey has caused problems
The issues usually appear years later. A homeowner builds a fence along the line drawn on a mortgage survey; a new neighbour orders a boundary survey and finds the fence a foot onto their land. Or an addition is designed to the minimum side setback using a mortgage drawing, and the foundation inspection reveals the true line is closer than shown. In both cases, the cost of a boundary survey at the start would have been far less than moving a fence or redesigning a wall.
Upgrading to a boundary survey
If you need a boundary survey and already have a mortgage survey, contact the firm that prepared it. Some can upgrade the work with a field visit to recover or set corners, which may be faster than starting from scratch with a new firm. Bring your deed, plat and any older surveys to the conversation.
Using either one for your project drawings
For most decks, sheds, pools and fences set well inside the lot, a site plan drafted from your existing records, including a mortgage survey and the recorded plat, gives the permit office what it needs. Where a boundary is uncertain, the honest answer is a boundary survey first and a site plan second.
Frequently asked questions
Is a mortgage survey a legal survey?
It is prepared by a licensed surveyor, but for a limited purpose. It usually does not establish the boundary to the standard needed for construction or disputes.
Can I build a fence using my mortgage survey?
Not on the line. If the survey says it is not for fence construction, build well inside the line or get a boundary survey first.
Do lenders still require mortgage surveys?
Practice varies by state and lender. Many rely on title insurance instead; some still require a location survey or full survey.
Is a mortgage survey the same as a plot plan?
No. A plot plan is a permit drawing showing a proposed project. A mortgage survey shows existing improvements for a lender.
Does title insurance replace a survey?
Not completely. Standard title policies often exclude matters a survey would reveal, such as encroachments, unless a survey is provided or extra coverage is bought.
