Philadelphia Property Tax Assessment Appeal Tool

For Philadelphian home-owners whose property tax is too high, they can answer some simple questions to build a high quality appeal automatically sent to the city to try to lower it.

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Inspiration

Amongst other ways we help, caseworkers at Community Legal Services help Philadelphia homeowners file appeals about the tax assessment of their homes. The tax assessment process is confusing and inaccessible, and many homeowners don't know how to best frame their appeals.

During the last round of new assessments (released in 2024 for tax year 2025), average residential property assessment is increasing by 19% Citywide, but increases are much higher in some neighborhoods.

  • Kingsessing (50%)
  • Parkside (36%)
  • Olney/Southwest (34%)
  • Allegheny West/Tioga/Nicetown (32%)

A 2022 study by Reinvestment Fund found that properties in Black and Brown neighborhoods are more likely to be assessed inaccurately high, relative to majority-white OPA (Office of Property Assessment) zones.

This means that homeowners in the affected zones are paying more than their fair share of property taxes, relative to their actual property values.

These are also the neighborhoods where tax foreclosures are the most concentrated, posing a threat to intergenerational wealth.

National data suggests that property owners in Black and Brown neighborhoods are less likely to file assessment appeals, which, over time, exacerbates the already-existing inequity in property tax assessments.

New assessments are coming out in the spring of 2026, for 2027 tax bills. We anticipate that homeowners in some Philadelphia neighborhoods will see significant increases to their property tax bills. We hope to encourage homeowners to file assessment appeals, and providing them with clear information about how to win those appeals.

What it does

This tool is a webpage that works on desktop and mobile web browsers. Philadelphian homeowners whose houses are overassessed by the city government can come in, answer some simple questions, and have a high-quality appeal and letter sent to the Office of Property Assessment (OPA) and the Board of Revision of Taxes (BRT). Both offices can determine whether an appeal is approved, and one approval from either counts.

At the end of the process, two emails are sent to OPA and BRT with each office's form, an appeal letter, and appropriate documentation. We set the homeowner's email address as the "From" email so that if an office responds, they will get that response. We also will "BCC" the homeowner so they can have a record that they sent it since it wouldn't be saved to their email's "sent" box.

How we built it

We used Docassemble a free and open source guided interview builder that is locally invented and maintained and is easy to self-host. CLS already has a self-hosted Docassemble site where we host various guided interviews for Philadelphians.

With some python, a single .yml file, and a few templates, we were able to work together to write out the interview and include data that the city has about the house to help them estimate a more accurate value of their home.

Challenges we ran into

  • The dataset that OPA publishes on OpenDataPhilly is LARGE and pulling all the properties from their API dramatically slows the website at the start
  • OPA's methods for assessing the value of properties is very opaque and without knowing exactly how it works, it is difficult to come to help the homeowner calculate it based on the facts of their home
  • Giving the homeowner tools and hints to find an accurate value feels pretty dinky, but more robust tools are hard without a person with expertise in this looking it over

Accomplishments that we're proud of

  • This will help Philadelphians lower their tax bills and pay their fair share of property taxes
  • This gives homeowners significantly more transparent and clear information about how tax assessments are calculated
  • We were able to put together the tool very quickly and get past some small hurdles at the start
  • Between our team we had great ideas to help out with the many questions we came in with
  • A great diversity of skills and knowledge helped us work in tandem throughout

What we learned

  • How to use Docassemble
  • About how seemingly simple processes require special knowledge or else are very opaque
  • Building out systems at a city level can be built with simple tooling

What's next for Philadelphia Property Tax Assessment Appeal Tool

  • Refining and testing
  • UX improvements
  • When 2027 assessments come out in May or June we can launch right away to help people
  • A more robust value calculator in the backend

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