If you’re purchasing a new property or subdividing your existing land, you may have heard the terms “Certified Survey Map” and “Plat of Survey” thrown around. While they both refer to a document that details the boundaries of a property, they have different purposes and requirements. In this article, we’ll explore the differences between a Certified Survey Map and a Plat of Survey to help you understand which one you need for your particular situation.

Certified Survey Map (CSM)

A Certified Survey Map, or CSM, is a document that shows the layout of up to four newly created lots, (creating more than four lots would require a Subdivision!) Typically, a CSM is used to divide a single parcel of land into multiple lots for sale or development. The map must be prepared by a licensed surveyor and approved by the local government or planning commission before it can be recorded.

The CSM includes a detailed survey of the property, showing the location of all existing and proposed improvements, such as buildings, roads, and utilities. It also includes information about the lot sizes, dimensions, and any easements or other restrictions that may affect the property. In general, a CSM is used for commercial or residential development, and it is often required by local zoning ordinances.

Plat of Survey

A Plat of Survey, on the other hand, is a document that shows the boundaries and improvements of an existing property. It is typically used to establish a description of a property, resolve boundary disputes, or obtain building permits. A Plat of Survey must also be prepared by a licensed surveyor and must meet minimum legal requirements as established by the State of Wisconsin.

The Plat of Survey includes a detailed survey of the property lines, showing the location of all improvements and boundaries, as well as any easements or other restrictions. It is important to note that a Plat of Survey typically includes information about lot sizes and dimensions, as it is focused on the boundaries of the property itself. It is often used for residential or commercial properties that are being sold, purchased, or refinanced.

Key Differences Between Certified Survey Map & Plat of Survey

The main difference between a certified survey map and a plat of survey is their purpose. A CSM is used to create a new subdivision of up to four lots, while a Plat of Survey is used to describe the boundaries and improvements of an existing property.

Another key difference between the two documents is the level of review and approval required. A CSM must be approved by the local government and / or county, while a plat of survey typically only requires preparation by a licensed surveyor. This is because a CSM will create additional parcels and may require changes to zoning or other regulations.

Finally, the cost and timeline for creating a CSM or plat of survey can vary significantly depending on the complexity of the project. A CSM may take longer and cost more due to the additional review and approval required, as well as the need to create new infrastructure or other improvements. A plat of survey, on the other hand, may be a quicker and less expensive process since it is only showing the existing boundary and visible improvements.

In some cases, both a CSM and a plat of survey may be required. For example, if you are developing a property that includes existing structures or improvements, a plat of survey may be needed to establish the boundaries of the existing property, while a CSM may be needed to create new lots. Wisconsin allows for up to four lots per property when using a CSM for lot division. If more than four lots are desired, a subdivision plat may be used for the division. Subdivision plats generally require more scrutinized review and approval processes. 

Which One Do You Need?

The decision about which document you need will depend on your specific situation. If you are purchasing or refinancing an existing property, a plat of survey may be sufficient. However, if you are creating new parcels, you will likely need a CSM or a Subdivision Plat to establish the lot sizes, dimensions, and infrastructure requirements. Contact Cardinal for your surveying needs.