Freddie Mac Guidelines: Uniform Appraisal Dataset (UAD)

What the Uniform Appraisal Dataset Means for Your Home Purchase

When you apply for a mortgage backed by Fannie Mae, your lender orders an appraisal to determine your home's value. That appraisal must follow strict formatting rules called the Uniform Appraisal Dataset, or UAD. Think of UAD as a standardized language that all appraisers must speak when describing properties.

The UAD tells appraisers exactly how to fill out specific fields on the appraisal report. Instead of writing "good condition," an appraiser must select from predetermined condition ratings like C3, C4, or C5. Instead of describing a kitchen as "updated," they must use specific terminology that matches UAD requirements.

Your appraiser might describe your home's exterior as "vinyl siding" in one section, but the UAD requires them to code it as "VinylS" in the data fields. This standardization lets Fannie Mae's automated systems read and analyze thousands of appraisals consistently.

Which Appraisal Forms Require UAD

Your appraisal will use one of several forms that must follow UAD standards. The most common is Form 70, the Uniform Residential Appraisal Report, used for single-family homes, townhouses, and PUD units.

If you're buying a condo, your appraiser will use Form 465, the Individual Condominium Unit Appraisal Report. For exterior-only inspections, they'll use Form 2055 for houses or Form 466 for condos.

Desktop appraisals use Form 70D, while hybrid appraisals (combining automated valuation with limited inspection) use Form 70H or Form 465H depending on property type. Each of these forms has specific UAD requirements that your appraiser must follow.

How UAD Affects Your Appraisal Process

The UAD doesn't change what your appraiser inspects or how they determine value. It only standardizes how they report their findings. Your appraiser still walks through your home, measures rooms, takes photos, and analyzes comparable sales.

The difference comes in how they document everything. Instead of free-form descriptions, they must select from dropdown menus and use specific codes. This creates more consistent data but can sometimes feel rigid.

For example, if your home has a partially finished basement, the appraiser can't just write "partially finished basement." They must indicate the percentage that's finished and use specific UAD terminology to describe the finish level.

What Documents Your Appraiser Needs

Your appraiser doesn't need additional documents from you because of UAD requirements. They still need the same basic information: property address, legal description, and access to the home for inspection.

However, UAD requirements might make your appraiser more thorough in documenting certain features. They may ask more specific questions about room counts, bathroom configurations, or heating systems to ensure they can complete the required UAD fields accurately.

If you've made recent improvements, having documentation like permits or contractor invoices can help your appraiser describe upgrades using the correct UAD terminology.

Why Fannie Mae Requires Standardized Appraisal Data

Fannie Mae processes millions of loans each year, and consistent appraisal data helps them assess risk more effectively. When every appraiser uses the same terminology and formatting, automated systems can quickly identify potential issues or flag appraisals for additional review.

Standardized data also improves quality control. If an appraiser consistently makes errors in UAD formatting, it becomes easier to spot patterns and provide additional training. This ultimately leads to more reliable appraisals for lenders and borrowers.

The UAD also supports Fannie Mae's automated valuation models. When appraisal data follows consistent formats, these models can better analyze market trends and property values across different regions.

Common Issues That Can Delay Your Loan

Appraisers who don't follow UAD requirements can create problems for your loan approval. If an appraiser submits a report with incorrect UAD formatting, your lender's quality control system may reject it automatically.

Missing or incorrectly coded UAD fields often require the appraiser to revise and resubmit the report. This can add several days to your loan timeline, especially if the appraiser is busy or unfamiliar with UAD requirements.

Some appraisers still struggle with specific UAD requirements, particularly around property condition ratings or room count standards. If your appraiser makes errors in these critical fields, it could affect your home's appraised value or require a completely new appraisal.

How UAD Updates Affect Your Transaction

Fannie Mae periodically updates UAD requirements to improve data quality and add new fields. The current version, UAD 3.6, becomes mandatory in November 2026, but appraisers can start using it earlier.

During transition periods, some appraisers may be more cautious about which version to use, potentially adding time to the appraisal process. If you're buying a home near a UAD update deadline, discuss timing with your lender to avoid potential delays.

Most UAD updates are minor and don't significantly impact the appraisal process. However, major updates can require appraisers to learn new procedures, which might temporarily slow down appraisal completion times in your market.

Working with Your Lender on UAD Requirements

Your lender's appraisal management company should ensure that assigned appraisers understand current UAD requirements. However, you can help by providing clear access to your property and answering any specific questions your appraiser has about features or improvements.

If your appraisal gets delayed due to UAD formatting issues, ask your lender about the specific problem and estimated resolution time. Sometimes a simple revision takes just a day or two, while other issues might require selecting a different appraiser.

Understanding that UAD requirements exist helps set realistic expectations for your appraisal timeline. While most appraisers handle UAD formatting correctly, knowing about these requirements helps you understand potential delays and work with your lender to resolve issues quickly.

References

For the official guidelines, see 5606.1: Uniform Appraisal Dataset (UAD) in the Fannie Mae Selling Guide.