MyDETax: Turning Public Data into 215,000 Personalized Property Tax Pages

New Castle County, Delaware completed its first property reassessment in over 40 years in 2024. All 214,788 parcels were evaluated and updated, correcting values that had been frozen at 1983 levels since Delaware courts mandated the change. For most homeowners, it was the first time their property had been looked at in their lifetime.

When the first round of tax bills went out in July 2025, a lot of residential property owners got a surprise. Home values had increased significantly compared to commercial and non-residential properties over the decades since the last assessment, which meant homeowners were now carrying a larger share of the tax burden. Bills were noticeably higher for many residents, and people were frustrated. Blame was being directed at school districts, the county, politicians, pretty much everyone involved. Kevin was in the same position as his neighbors. He got a higher bill, wasn't sure what happened or why, and started digging into his own property data to figure it out. That research is what eventually became MyDETax.

House Bill 240 was the legislative response. Signed in August 2025, it allowed school districts to charge separate rates for residential and commercial properties, giving districts the ability to bring residential bills back in line. Five school districts, each setting their own split rates, covering all 215,000 parcels in the county. In theory, it addressed the imbalance, but residents had no way to know what it actually meant for their specific property. The county didn't have a tool for that.

Tax bills were posted to the county website on November 17, 2025, though most residents wouldn't see them until mailed copies arrived a week or two later.

MyDETax has 215,000 individual property pages, one for each parcel in New Castle County. Each page is generated on the fly with its own content, its own tax calculation, and its own interactive map. To put that in context: a typical small business website has somewhere between 5 and 20 pages. A large e-commerce store might have 10,000 to 50,000 product pages. This site has 215,000, all built by one person in about two weeks.

The core of the tool is a custom tax calculation engine. It figures out each property's school tax under the new split-rate system, applies the correct rate for whichever of the five school districts the property falls in, and detects whether the owner received Delaware's senior tax discount. That last part required some reverse engineering since the eligibility data wasn't published anywhere in usable form. Kevin worked backward from billing patterns to flag which properties had the credit applied. The result for each resident is a clear side-by-side: their 2024 tax, their 2025 tax as billed, their estimated corrected tax under the new rates, and the dollar difference.

Each property page also pulls in the relevant state and county legislators for that address, so residents know who to contact if they have questions.

Traffic built steadily through the fall, then jumped sharply in early December. When official bills hit mailboxes on November 17, residents opened them, had questions, and searched their address. MyDETax had already indexed all 215,000 addresses, and Google had already found them.

Between October and December 2025, the site reached 15,100 unique visitors, 17,100 visits, and 31,300 page views. Eighty-five percent of that traffic came from organic Google search, with no paid advertising at any point. People searched for their address and found a page built specifically for their property.

The City of Wilmington linked to MyDETax directly from wilmingtonde.gov because it was the most useful resource available for residents trying to understand their bills. The site was also picked up in local news coverage, none of which came from any outreach or promotion. As of early 2026, it still pulls over 2,000 visitors a month.

MyDETax started as a civic project, but it demonstrated something that applies well beyond property taxes. There is real value in taking complex data that already exists and making it easy for people to find and understand their specific piece of it.

The same approach works for real estate companies that want to give clients better property search tools, title companies managing large volumes of transaction data, property managers tracking portfolios across hundreds of units, or any organization sitting on records that customers or constituents need to be able to look up and understand. The pattern is the same: the data exists, the need exists, and building the bridge between the two is a solvable problem.

A project along these lines typically starts around $15,000 depending on scope. If you have something similar in mind, get in touch.