How to Filter Your Property List by Slope Percentages

When it comes to land investing, slope can make or break a deal.

Properties with extreme slopes often lead to higher development costs, limited buildability, or even unusable acreage, making them far less attractive to buyers.

That’s why understanding slope percentages is critical when evaluating land.

Land Portal’s slope filtering tool is a game changer, allowing you to target only the flattest, most buildable lots while filtering out steep or problematic terrain.

In this guide, we’ll walk you through exactly how to use the slope filter step by step so you can start building cleaner, higher-quality lists today.

Step 1: Start a New Search

To get started, log into Land Portal.

Begin by setting up your basic filters.

For this example:

Location: Ashtabula County, Ohio
Property Type: Vacant Land
Acreage Range: 20 to 100 acres

Use these filters as a starting point before applying slope data.

Step 2: Locate the Slope Filter Section

Scroll down to the Property Slope filter. This filter allows you to define the percentage of the property that falls within certain slope ranges.

Step 3: Understand How Slope Filtering Works

You can select from the following slope categories:

Under 5%
Under 10%
Under 15%

Then enter the percentage of the property you want to meet that criteria.

Example: If you select “Under 5%” and enter “30%,” this means at least 30% of the property must have slope under 5%.

If you enter “100%,” that means the entire property must be under 5% slope.

Step 4: Apply Slope Criteria for Your Area

Slope terrain varies by region.

Here's how to approach it:

Flat Areas (e.g., Ohio): You can use stricter slope filters, like 30% under 5% and 60% under 15%.
Hilly Areas (e.g., Kentucky, North Carolina): You may need to lower the thresholds or adjust your expectations, since flatter land is harder to find.

Step 5: Enter Your Desired Slope Filters

In this example:

Under 5% slope: Minimum 30% of the property
Under 15% slope: Minimum 60% of the property

These filters use “AND” logic—both conditions must be true for a property to appear in your results.

Once you've entered your slope criteria, click “Apply.”

Step 6: Review Your Filtered Results

After applying the filters, you’ll see how many properties match your criteria (e.g., 1,970 properties).

Now you’ve filtered out heavily sloped, unbuildable lots and are looking only at higher-quality properties.

Step 7: View Properties on the Map

Click “Show on Map” to explore your filtered list visually.

Click into individual properties.

Scroll down to view slope breakdown:

% of property under 5% slope

% of property under 15% slope
% of property over 15% slope

Verify that the properties meet your slope criteria before exporting.

Step 8: Export Your Clean List

Once you're satisfied with your results:

Return to your filtered list.
Click “Export” at the bottom of the page.

This will export your high-quality list that excludes sloped or defected land.

Step 9: Combine with Other Filters (Optional)

Enhance your filtering even further by combining slope filters with:

FEMA Flood Zones
Wetlands
Road Frontage
Landlocked Filter

This ensures you're pulling the cleanest possible data, without wasting records on low-potential properties.

Using Land Portal’s Slope Filter is one of the most powerful ways to streamline your data and invest in smarter, cleaner land deals.

By removing sloped, risky properties from your lists before exporting, you save money and increase the chances of finding profitable, build-ready land.

If you haven’t already, log in to Land Portal now and start refining your searches using the slope tool.

You’ll be one step closer to closing better deals with less effort.