What Is a Plat and Do You Need One?

If you’re in the market for a new home, you might wonder, “What is a plat map?” The plat map, devised in the mid-1800s to help document rural land ownership within the United States, is actually a useful document to have. The more you understand it before buying a home, the better.

Plat map definition: What is it?

“Homeowners are going to want to see plat maps if they are interested in clearly establishing their property lines, or are looking to sell part of their property or buy part of a neighbor’s property,” said Martin Orefice, the founder of Rent to Own Labs.

Plat maps are surveyed maps that show how a larger parcel of land is divided or subdivided within your county or city. “These maps are drawn to scale using something called ‘metes and bounds,’ and generally show the tract of property size and boundaries,” said Curtis Jackson, a licensed attorney in California and head of regulatory and permitting at SnapADU. “They also contain all the information required to subdivide, merge or develop a parcel.”

A properly drawn plat map shows the placement of property lines, streets, alleys, bodies of water, parks and other physical features of the land exactly as they are recorded with the county.

How to read a plat map

A plat map can often be read like a normal map, with various elements of the properties listed as numbers. “The shape of the parcel, dimensions and house numbers are used to locate the parcels on the map,” said Jeff Johnson, a real estate agent and acquisition manager at Simple Homebuyers. “Numbers on the bottom of the parcel indicate width, while the numbers at the right indicate the depth of the parcel.”

The scale of the plat map is mentioned in the map’s legend. Dotted or straight lines indicate the parcel boundaries.

What if a property is not platted?

While a plat map can be useful for a potential home buyer, it’s also not the end of the world if you don’t see one before buying. “The biggest drawback is you won’t have a clear sense of your property lines or if the property can be subdivided and sold.” If those things are important to you, look at a plat map—or ask to have one made (more on that below)—before purchasing a home.

Luckily, because real estate transactions require title insurance, plat maps are often required and used as part of a title search to confirm that the seller has the right to convey the property described. This also helps the buyer ensure that the property is what they think they are purchasing.

Additionally, because most plat maps started on original rural lands, most properties have at least one older plat map associated with it, said Jackson. However, “if the land around the house hasn’t been fully surveyed or divided into different lots, your house might not be found anywhere on a plat map until there’s more development around it,” he said. “This would typically happen in undeveloped, rural areas.”

If your property doesn’t come with a plat map and you think you might need one, you can always have one made. In that case, “you should consider platting your property by hiring a licensed surveyor to get your property platted,” Johnson said. “The surveyor will gather geographical data of that area and survey the property to get it approved by your area’s planning and zoning commission.”

Plat vs. survey: What’s the difference?

Survey maps have most of the same property line information that you’ll find in a plat map, but they’ll also include more data about the land itself, like elevation and slope.

Do you need a land survey if the plat map is wrong?

If a plat map is wrong and the property owner wants to subdivide the property further or develop the land, you’ll need a new land survey. Just keep in mind that “plat maps are not as accurate as a land survey,” said Jackson, “and as such, a survey may also be required.”

Since plat maps are useful for ensuring the rightful ownership of property, it doesn’t hurt to have one available. If you decide to get a new one made, you may need a title search to find any changes in ownership as a first step toward updating a plat map.