A judge ordered it in 2017, and it landed in 2021
Delaware County’s assessments had been sitting on a 1998 base year. In 2017 a judge of the Court of Common Pleas ordered a countywide reassessment, Tyler Technologies revalued more than 200,000 parcels, and the new roll took effect for tax year 2021.
Twenty-three years of market movement showed up on one bill. Some assessments barely moved. Others doubled. That’s what a reassessment does: it doesn’t add up the total tax, it moves the shares around.
Values went up, so the rates came down
State law forces that. Under 53 Pa.C.S. section 8823, in the first year on a new roll every taxing district has to cut its rate so the total levy doesn’t exceed the prior year’s. By a separate vote it can then set a final rate up to 10% above the prior levy, and anything higher needs court approval. New construction is excluded from the math, and school districts run under a different section of Act 1.
You can watch it happen in the county’s own numbers. Delaware County called the reassessment revenue neutral and calculated a 2021 millage of 3.112, down from 5.461 in 2020. The rate fell by almost half because the values it was applied to had grown.
A Delco mill and a Bucks mill measure different things
This is the part that confuses buyers coming across a county line. Bucks County still assesses off 1972 values. Chester County off 1996. Delaware County off 2021.
A Bucks school district charging 204 mills and a Delco district charging 22 can land on the same annual bill, because the number being multiplied is completely different. Comparing millage across counties is arithmetic with two different units. Never do it.
Three bills, and they stack
Every Delco house pays county, municipal and school. The county’s 2026 rate is 4.609 mills, and it’s normally the smallest of the three. School is normally the biggest.
Here’s what the stack looks like in four places, using the county’s 2026 tax-rate table:
| Municipality | County | Municipal | School | Total | Per $100,000 assessed |
|---|---|---|---|---|---|
| Springfield Township | 4.609 | 4.25 | 22.8326 (2026-27) | 31.69 | about $3,169 |
| Nether Providence | 4.609 | 3.7206 | 31.9076 (2026-27) | 40.24 | about $4,024 |
| Swarthmore | 4.609 | 4.446 | 32.1605 (2026-27) | 41.22 | about $4,122 |
| Darby Borough | 4.609 | 18.40 | 32.86 (2025-26) | 55.869 | about $5,587 |
The first three rows carry their district’s adopted 2026-27 school rate; Darby Borough’s total runs off the 2025-26 school rate still printed on the county table. Same county, same year, and the bill on an identically assessed house nearly doubles across those four rows. The municipal line is the one that varies most in percentage terms and matters least in dollars.
0.0000 and 18.40
The county’s 2026 tax-rate table shows municipal rates running from 0.0000 mills in Thornbury Township to 18.40 in Darby Borough. Neither number means what it looks like.
Thornbury’s owner still gets a county bill at 4.609 mills and a West Chester Area School District bill at 12.22 mills for 2026-27, so the real stack is about 16.83 mills, or roughly $1,683 per $100,000 of assessed value. A zero on the municipal line moves the work to the other two lines; it doesn’t delete the tax.
Darby Borough’s 18.40 is the highest municipal rate on that table, and it’s still under a third of the borough’s total stack of 55.869 mills. Judge a house by the total, and only after you know its assessed value. Ask for the actual bills, not the listing sheet’s estimate.
The county’s own line moved for 2026
County millage went to 4.609 mills for 2026, up from 3.8730 for 2025. The county described the budget as a 19% revenue enhancement and put the average increase at about $185 a year per homeowner. It was adopted December 10, 2025.
If you’re buying now, the escrow your lender builds should be running off current figures, not the seller’s old bill and not the seller’s exemptions. Ask.
The homestead exclusion, and what it does not cover
The Act 1 homestead and farmstead exclusion reduces the assessed value used to calculate your school tax. School tax only. County and municipal bills are untouched.
You apply through your school district during open enrollment, December 15 through March 1, and there’s no fee. The county Board of Assessment processes it and replies within 30 days, and you can check any address on the county’s Real Estate Tax System to see whether the exclusion is already on it. Questions go to the Homestead Coordinator at 610-891-8747 or [email protected].
The dollar value is set district by district, so there’s no countywide number. As an example, Radnor Township School District takes $30,636 off an approved homestead’s assessed value. Buy in December and file in January; the exclusion does not follow the seller to you automatically.
Appealing, if the number is wrong
Delaware County takes annual assessment appeals. Forms come from the Board of Assessment, and the residential, commercial and exemption forms for the next tax year get posted on the county site. The filing rules are strict and unglamorous: original signature, and either postmarked or hand-delivered by the due date. Deadlines and fees move, so call the Board at 610-891-4273 and confirm before you rely on a date you read anywhere, including here.
The Board sits on the ground floor of the Government Center, 201 W. Front Street in Media. If the decision goes against you, you have 30 days to take it to court through the Office of Judicial Support.