Easy methods for Address to Parcel lookups

Using addresses to lookup parcel numbers is essential for tasks in real estate, government, and land development. A parcel number, or Assessor's Parcel Number (APN), is a unique number assigned to each parcel of land by a county tax assessor. This number plays a role in accurately identifying, taxing, and managing legal matters related to the property.

This guide will take you through the basics of address-to-parcel conversion, introduce tools like the Placekey API, and address common challenges you might face. You'll also find real-life examples showing how these methods are used in different scenarios.

By the end, you'll be well-equipped to convert addresses to parcel numbers accurately and efficiently, whether you're dealing with single or multiple addresses.

1. Basics of looking up a parcel number with an address

To demonstrate the process of address to a parcel number, let's use the example of 2200 Broadway, New York, NY 10024.

For a single address there are several options available. Many counties and cities offer parcel lookup services; for example, New York City has its own service. However, we'll be using Regrid’s service, which includes a map interface.

On Regrids map, search for "2200 Broadway," and the map will highlight the parcel, displaying a card with more details about the parcel.

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With a bit of scrolling, you can find the parcel number, listed as the Parcel ID:

This works great for individual address but if you have thousands you need to lookup an API is a better option.

2. API Methods

The Value of API Services for Automation

When dealing with large datasets API services are most efficient. APIs allow you to automate the process of using street addresses to lookup parcel numbers, reducing manual work and minimizing errors. They’re particularly useful when you need to process multiple addresses at once or integrate parcel data directly into your systems. Prominent parcel data API services include Zillow and Regrid. Many municipalities also offer GIS APIs that include parcel data but are limited to the individual municipality. 

Using the Placekey API

Placekey can help convert addresses to parcel numbers. Placekey not only provides a unique identifier for locations, but also returns parcel numbers and geocodes, providing additional context about the location and address. 

Here’s how you can use the Placekey API:

1. Get Your API Key: Sign up for an API key on the Placekey website.
2. Download the Notebook: we have a template notebook hosted on Colab here.
3. Customize and run: Change fields to match your data, then run the noteboo
4. ‍Join the data: Use Placekey to join the Parcel number back to your dataset

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3. Common challenges

Messy Addresses

When working with address data, you often encounter improperly formatted and difficult-to-parse addresses. This often makes lookup parcel numbers from an address, as many services expect addresses to be well-formed. A common way to solve this problem is to standardize addresses.

Address standardization transforms addresses to conform to some standard, parsable format. There are several ways to accomplish this, ranging from creating your own to using an external service. 

Placekey handles this for you and can handle common messy addresses. This simplifies the process of converting address data into parcel data, as the entire flow is handled by a single service.

Federated Parcel Number Standards

Datasets with addresses from multiple states, or even multiple counties within the same state, often contain duplicate parcel numbers that refer to different parcels of land. Parcel numbers serve as unique identifiers within the jurisdiction of the body responsible for assigning them. However, this means that if working with data from multiple jurisdictions, you’ll need a second identifier to ensure uniqueness. 

Placekey returns GEOIDs and RESO's Universal Parcel Identifiers. GEOIDs are federally-designated identifiers that allow us to distinguish between different regions of various sizes. For example, a 2-digit GEOID identifies a state, and a 5-digit GEOID identifies a county within a state. 

RESO is a Real Estate Standards Organization, is an organization focused on establishing common standards for the handling of data within the Real Estate industry. The purpose of this effort is to increase efficiency in an increasingly nationalized, even globalized, housing market. In keeping with this, the Universal Parcel Identifier is a RESO-specified protocol for combining GEOIDs with parcel numbers, which can be used as a single universal identifier for any parcel in the United States. 

4. Understanding Parcel Numbers

What is a parcel number?

A parcel number, or Assessor's Parcel Number (APN), is a unique identifier assigned to a piece of land by the local tax assessor. It’s used to track property ownership, taxation, and legal boundaries. Each parcel number corresponds to a specific plot of land, ensuring accurate records and transactions.

Why addresses to parcel numbers?

Looking up a parcel number from an address makes verifying property ownership, accessing public records, and conducting real estate transactions simpler. It ensures that the property in question is correctly identified and linked to the right legal and tax records. This is important to having a comprehensive understanding of a property, which often requires linking information spread across multiple documents. Being able to use parcel data as a common language can speed up this process and reduce the likelihood of costly errors. 

What are some use-cases of parcel numbers?

There are great case studies that show the variety of ways in which people are using parcel data each day. Some highlights include:

• The city of Detroit using parcel numbers to facilitate an enormous program to eliminate urban blight
• A study by climate central analyzing the impact of rising sea levels on properties in coastal areas
• A real estate development company who uses parcel data to analyze investment opportunities at scale
• A case study by Corelogic demonstrating how an insurance company used parcel data to respond more efficiently to natural disasters
• RESO’s collection of case studies and whitepapers demonstrating the value of using standard data formats, like parcel numbers

These are just a few of the many reasons you could want to convert from address to parcel number.

5. Conclusion

Converting addresses to parcel numbers is essential in real estate, urban planning, and legal work. This guide covered the basics of retrieving parcel numbers and introduced methods like using the Placekey API to retrieve this information.

With these tools, you can handle address-to-parcel conversions efficiently, whether for single properties or large datasets. By understanding common challenges and leveraging the right solutions, you’ll ensure accurate and streamlined property identification in your projects.