Brandywine Creek runs through the middle of Chadds Ford, and for most people who live near it, the water is scenery. A break in the tree line. A reason the light comes in at a certain angle in October. For anyone buying, selling, or settling an estate here, the creek does something else first. It is the county line. On one bank sits Chadds Ford Township, in Delaware County. On the other sit Pennsbury Township and the southern edge of Birmingham Township, in Chester County. The village center, where U.S. Route 1 crosses Route 100, falls on the Delaware County side. Chadds Ford Knoll and several of the newer developments that people mean when they say "Chadds Ford" sit in Chester County. Nothing on a listing sheet tells you which side of that line a property sits on. The tax parcel does.
That distinction stops being trivia the moment someone needs a septic inspection, applies for a well permit, or tries to reconcile two tax bills for houses that look nearly identical.
Two Health Departments, One Village
Since June 1, 2023, the Delaware County Health Department has handled permitting, inspection, investigation, and enforcement for individual and small community on-lot sewage systems within Chadds Ford Township, the Delaware County side of the community. The department's own sewage and water page, updated as recently as May 2026, confirms this covers both new system permitting and well construction, including private water wells and geothermal wells. Anyone on that side of the creek who needs a septic inspection or a well permit works through the department's Environmental Health Division, based in Eddystone, reachable at 484-276-2100.
The township itself didn't step entirely out of the picture. Chadds Ford Township still reviews permits tied to work on existing septic systems, things like additions or new pools, through its own inspector.
Cross the creek into Pennsbury or Birmingham Township, and the process changes completely. Chester County administers on-lot septic permitting through its own program, separate from Delaware County's structure. A homeowner on the Chester County side who calls the Eddystone office is calling the wrong department, and vice versa.
Wells, Water, and a Line That Doesn't Match
Water complicates the picture rather than simplifying it. Chadds Ford Township's own utilities page states that most properties in the township rely on an on-site well, though some parcels receive public water through Chester Water Authority. That sounds like a reasonable way to guess which county you're in until you check who else the authority serves. Chester Water Authority's own customer list places Chadds Ford Township, in Delaware County, alongside neighboring Concord and Thornbury townships. It also serves Pennsbury and Birmingham townships, on the Chester County side, plus Kennett Square and a separate Thornbury Township in Chester County. Public water from the same authority runs on both banks of the creek. Seeing "public water" on a listing tells you nothing about which county's septic office governs the rest of the property if part of the home still relies on on-site sewage.
For the wells that remain, a broader Pennsylvania Department of Environmental Protection water quality assessment identified more than a thousand miles of impaired streams in Chester County, and a separate U.S. Geological Survey review of Pennsylvania waterways found PFAS compounds in the majority of streams tested, with Brandywine Creek among the waterways where they turned up. Well owners carry the testing responsibility themselves. The general guidance for private wells in this region is an annual test for bacteria and nitrates, with a fuller panel covering pH, hardness, iron, manganese, and PFAS every three to five years. Municipal water customers don't carry that burden, which is one more reason to confirm the actual water source on a specific parcel before assuming anything based on the neighborhood name.
What Changes Across the Creek
| Delaware County side (Chadds Ford Township) | Chester County side (Pennsbury & Birmingham Townships) | |
|---|---|---|
| Septic permitting and inspection authority | Delaware County Health Department, Environmental Health Division | Chester County's own on-lot septic program |
| Permits for work on existing septic systems | Reviewed directly by Chadds Ford Township | Handled through the Chester County process |
| Public water provider | Chester Water Authority customers alongside private wells | Chester Water Authority customers alongside private wells |
| Unionville-Chadds Ford School District millage | Roughly 19 mills, per recent local market reporting | Roughly 34 mills, per recent local market reporting |
The Same School District, Two Different Bills
Both sides of the creek send children to Unionville-Chadds Ford schools, a district that consistently ranks among the strongest in the state. The tax mechanics behind that shared district differ by county, because school millage is levied against each county's own assessment system. Recent local market reporting puts the Unionville-Chadds Ford millage at roughly 19 mills for parcels on the Delaware County side and roughly 34 mills on the Chester County side, with Chester County's own countywide millage of 5.164 mills layered on top of that. Combined with township millage, the effective property tax on a Chester County side Chadds Ford home tends to run noticeably higher than a similarly priced home across the creek. Millage rates adjust from year to year, so confirming the current figures with the county assessor before writing an offer protects against a surprise on the closing disclosure.
Septic, Sewer, or Something Else
On the Delaware County side alone, a home's wastewater setup could be one of three different things. It might be on-site septic, now regulated by the Delaware County Health Department. It might be public sewer, run by the Chadds Ford Township Sewer Authority, which operates two municipal wastewater treatment plants and requires a sewer certification before settlement, a $40 request tied to the property address, the buyer's name if known, and the settlement date. Or it might run through a private community treatment plant, the kind that serves the Springhill Farm Condominium Association and Knights Bridge Association developments. Each path has its own paperwork, and an inspection contingency written for the wrong one costs time in a transaction where the calendar already matters.
Before the Inspection Gets Scheduled
A few steps sort out which rules apply before anyone picks up the phone:
- Confirm which township the parcel sits in, Chadds Ford Township, Pennsbury Township, or Birmingham Township, using the tax parcel rather than the mailing address.
- If the parcel is in Chadds Ford Township, on-site septic permitting and inspection now runs through the Delaware County Health Department, while additions or repairs to an existing system still go through the township first.
- If the parcel is in Pennsbury or Birmingham Township, contact Chester County's own on-lot septic program rather than Delaware County's office.
- Verify whether the home is on public sewer through the Township Sewer Authority or a private community system before assuming a septic inspection applies at all.
- Pennsylvania doesn't require a septic inspection statewide at the point of sale, but FHA and VA financing typically require proof the system functions, and Pennsylvania's Seller Disclosure Law asks sellers directly about the sewage system's type, age, and last pump date. A Penn State Extension fact sheet on septic inspections during real estate transactions walks through what a certified inspector actually checks.
- Older systems, particularly anything installed before the 1980s, sometimes lack risers or visible tank markers, which can extend an inspection. Building a wider scheduling window protects a closing date.
For a probate executor working against a court timeline, or an out of area buyer trying to close on a fixed schedule, sorting out which county's paperwork applies isn't paperwork for its own sake. It's the difference between a clean closing and a deal that stalls on a call to the wrong department. Between a construction and environmental consulting background and hands-on experience with exactly this kind of county line property, Greg Davis walks Chadds Ford buyers, sellers, and executors through this due diligence before an offer goes in or a listing goes live.
FAQ
Does Pennsylvania require a septic inspection before selling a home in Chadds Ford? No state law mandates it, but most lenders do in practice, and Pennsylvania's Seller Disclosure Law requires sellers to answer specific questions about the sewage system regardless of financing type.
Which office do I call first if I don't know which county my Chadds Ford property is in? Start with the tax parcel number on the property tax bill or plat map. It identifies the county and township before either health department gets a phone call.
Is Chadds Ford's public water the same everywhere? No. Chester Water Authority serves customers on both sides of the county line, so having public water doesn't indicate which health department oversees the septic system if part of the property still uses on-site sewage.
