TL;DR: Impact fees are one-time charges a city collects when you build, meant to cover the cost your project adds to public infrastructure — roads, schools, parks, water and sewer capacity. They're separate from your building permit fee and they vary enormously from one city to the next for the same house. They're usually due at permit issuance, which means they hit your budget before you've poured a foundation.
The line item that isn't on the permit fee schedule
When people budget for "permits," they look up the building permit fee — often a few thousand dollars tied to construction valuation. Then the impact fees arrive and the number triples. Impact fees are a completely separate assessment, calculated differently, and in high-growth markets they can be the largest single soft cost in the entire project.
The logic is straightforward: a new house adds a car to the roads, kids to the schools, demand to the water system. Impact fees (sometimes called "development impact fees," "system development charges," or "capacity fees") are the city's mechanism to make new development pay for the infrastructure it consumes, rather than spreading that cost across existing taxpayers.
What the fees actually fund
Most jurisdictions break impact fees into categories, each with its own rate:
| Category | What it funds |
|---|---|
| Transportation / road | Capacity on roads and intersections |
| School | Classroom and facility capacity (often the largest) |
| Water & sewer | Treatment and distribution capacity |
| Parks & recreation | Open space and facilities |
| Fire / public safety | Stations and equipment |
| Drainage / stormwater | System capacity |
A single-family permit might be assessed in five or six of these categories at once. The water and sewer "connection" or "tap" fees alone can be the largest line in capacity-constrained western and coastal cities.
Why the spread between cities is so large
Impact fees track two things: how fast a region is growing, and how expensive its infrastructure is to build. The result is a wide spread between low-fee and high-fee metros for an identical house.
- Lower-fee markets — where land is plentiful and infrastructure is cheaper to extend — tend to charge less.
- Higher-fee markets — fast-growing metros with expensive infrastructure — tend to charge the most.
No national fee table is on record here; each city's schedule is the record.
This is why fee trends matter as much as approval speed: a fast timeline in an expensive fee market is only half a win. The cities that are easiest to build in combine quick approvals with predictable, moderate fees.
When they're due — and why timing matters
Most jurisdictions collect impact fees at building permit issuance, though some defer to certificate of occupancy. Either way, it's cash you need relatively early, and it's generally not financed by your construction loan the way hard costs are.
For a developer running a pro forma, impact fees are a front-loaded cost that drags returns the longer the project sits. For a homeowner, they're the difference between a budget that holds and one that blows up at the permit counter. Either way: find the number before you close on the land.
How to find your number
- Pull the city's impact fee schedule. Most publish it online, often as a PDF tied to an ordinance. Search "[city name] impact fee schedule."
- Match your project type. Fees are typically per dwelling unit for residential, per square foot or per fixture for some categories.
- Add the categories that apply. Don't stop at the road fee — water, sewer, school, and park fees stack.
- Check for credits or exemptions. Infill, affordable housing, and ADUs sometimes get reduced or waived fees. ADU projects in particular are often partially exempt as a housing-supply incentive.
A Buildability™ report flags the jurisdiction and its permitting profile so you know which fee schedule to pull — and the city pages summarize the fee environment for major metros. For the exact dollar figure on a specific parcel, the city's current schedule is always the authority.
Budgeting rule of thumb
Until you've pulled the actual schedule, carry a placeholder, and size it from a city you have a schedule for, not from a national average. Err high in fast-growing metros and confirm. The goal isn't precision at the screening stage — it's not being shocked at the permit counter.
Score any address free — know the jurisdiction and its permitting profile before you make an offer.
