Why can a simple patio or driveway trigger stormwater review?
Imagine a 12-by-20-foot strip of lawn beside a house. During a heavy rain, some water can soak into the soil. Replace that area with concrete and more rain may travel across the surface toward the street, a storm drain, a neighbor's yard or the home's foundation. A small change on one property can add to downstream runoff when it occurs on many lots.
Stormwater management addresses where rainwater goes and how increases in runoff are controlled. Zoning addresses where and how improvements may be placed on a lot. An entirely different approval may be needed when work reaches a public road or right-of-way. These questions can overlap, but they are not interchangeable.
Pennsylvania's Act 167 stormwater program requires county watershed planning and corresponding municipal regulations. For a typical household project, the most useful first source is therefore the specific township, borough or city responsible for the parcel—not a generic statewide list of driveway permits.
Which outdoor improvements can affect impervious area?
Municipalities use terms such as impervious surface or impervious coverage to describe areas that prevent or limit water from soaking into the ground. Paving, concrete, rooftops and many other constructed surfaces can count. The precise classification is set by the local ordinance and the approved drainage design.
The following table shows the questions to investigate for common projects; it is not a statewide permit-decision chart.
| Project | Why it may be reviewed | What to ask the office |
|---|---|---|
| New concrete patio | Previously vegetated ground becomes hard surface | Impervious-area calculation, zoning, location, runoff control |
| Driveway widening | More pavement and possible change near the street | New area, access width, right-of-way or road-occupancy rules |
| Existing driveway resurfacing | May not add area but local permit requirements can remain | Whether like-for-like work is treated differently from expansion |
| Gravel parking pad | Compacted or non-vegetative surfaces may count locally | How gravel and proposed base layers are classified |
| Permeable-paver patio | Performance depends on installation, soil and drainage design | Whether the ordinance credits the specific design as pervious |
| New sidewalk or walkway | Small additions can still affect lot coverage and drainage | Site plan, setbacks, right-of-way and stormwater paperwork |
Don't assume that material labels settle the question. A permeable product is not automatically classified as pervious for every municipal calculation. Likewise, removing an existing driveway and putting another one in the same footprint may be treated differently from paving new lawn—but that answer belongs to your local government.
Four actual York County examples: the rules aren't identical
The examples below come from the respective municipalities' published websites as reviewed on November 2, 2026. They are not York County-wide requirements. Verify the property municipality and current forms before relying on any example.
Spring Garden Township: extra hard surface means an additional application
Spring Garden Township's building-permit page places driveways, walkways and uncovered patios among its zoning-permit examples. It also states that any additional impervious surface—including patios, driveways, sidewalks, pads, buildings and other listed improvements—requires a Stormwater Management Permit Application in addition to applicable building or zoning paperwork.
Spring Garden asks applicants to provide a site diagram showing existing and proposed impervious square footage. If someone plans to add a 10-by-12-foot patio where there is now grass, a useful first step is identifying the new 120-square-foot footprint and drawing exactly where it sits on the lot. That calculation is not a determination that the project will be approved or that a particular drainage facility is required.
West Manchester Township: a published stormwater fee and onsite control rule
West Manchester Township's Zoning & Codes page says that new impervious area added to a property is subject to a $1 per square foot stormwater fee and that the resulting water must be managed or infiltrated on the site. The township dates this posted policy to January 1, 2013.
For example, 240 square feet × $1 equals a $240 illustrative stormwater fee if that full 240 square feet is assessed as new impervious area under the township's currently posted policy. This example does not include zoning fees, design or construction costs, credits, waivers or exemptions. Ask West Manchester to confirm the latest fee schedule and how your particular project area is calculated before estimating a payment.
The same township lists uncovered concrete or paver patios and repaving, replacing or widening driveways among zoning-permit examples. It separately lists seal-coating a driveway as work for which no permit is required. Those distinctions demonstrate why “I'm only working on an existing driveway” is not enough information for a reliable answer.
Springettsbury Township: bring a complete site plan to the permitting process
Springettsbury Township's official FAQ says permits are needed for most work and describes residential site plans showing lot and structure dimensions, driveway width and length to the right-of-way line, setbacks, and easements. The township also maintains a stormwater management resource page.
For a proposed driveway addition or parking pad, that means you should come prepared with more than the estimated pavement area. Be ready to show the existing driveway, intended access, nearby structures, lot boundaries and drainage direction. Confirm the township's current application and any stormwater questionnaire or other supporting documents for your project. The township's general FAQ does not establish a single universal patio-area exemption.
City of York: online zoning and stormwater submissions
The City of York Bureau of Planning and Zoning says that its planning and zoning applications are completed through OpenGov. The bureau's published application list specifically includes driveways, patios and concrete pads among projects served by the zoning-permit route, while the portal also handles stormwater management plans.
The city has its own stormwater management program. A York mailing address is not proof that a parcel is within city boundaries; verify the actual municipality before opening an application.
Calculate the proposed surface area (square feet)
A basic area estimate is useful before you call the permitting office. For a rectangle, multiply length × width. If your patio is L-shaped, divide it into non-overlapping rectangles, calculate each area and add them together. Keep existing pavement separate from proposed new pavement so the municipality can determine the change in coverage.
Simple rectangular surface-area calculator
Enter feet, not inches. The tool calculates proposed footprint only. It does not decide whether a permit or stormwater fee applies.
Privacy: Inputs are calculated in your browser; they are not sent to the website. No results represent a permit approval.
For instance, a 12 × 20-foot patio is 240 square feet; adding a 3 × 25-foot path would add another 75 square feet. If both cover previously vegetated land, the combined proposed footprint is 315 square feet. A real submission may also need to account for other proposed roofs, additions or pavement, and how existing coverage is being removed or changed.
Existing vs. newly covered area: Don't deduct a demolished surface or assume that any gravel automatically counts as existing impervious area without checking the municipal ordinance. The municipality decides what the approved baseline is and how increases or redevelopment are classified.
What happens to the rainwater after the work?
Coverage is one part of the review. The office may also want to know where runoff flows: toward a foundation, into a street drain, across a neighboring parcel, downhill to a stream, or into an existing approved facility. A drawing of a patio without existing grades, slopes or drainage paths may not answer that question.
Downspouts, grading and the route to the street
Document any roof downspouts, visible low points, swales, catch basins or drainage pipes affected by construction. A contractor might propose pitching a patio away from the house, but that does not automatically authorize discharging concentrated water onto adjoining land or into a public right-of-way. Ask the municipality if the grading plan or discharge location must be reviewed.
Potential runoff controls
Depending on local regulations and site conditions, a reviewer may discuss infiltration beds, seepage pits, dry wells, rain gardens, detention or other practices. These are possibilities, not instructions to install a particular system. The correct design depends on soils, nearby foundations, groundwater, utilities, slope and any applicable engineering standard.
The Pennsylvania Department of Environmental Protection's homeowner stormwater resources explain why runoff and pollution matter and discuss rain gardens, rain barrels and other conservation approaches. An educational example is not a substitute for a permitted design.
Does a large project need separate state approvals?
Some larger earth-disturbance projects can trigger Pennsylvania DEP's Chapter 102 construction stormwater requirements. That is a separate regulatory question from routine municipal zoning and stormwater paperwork. A typical small residential patio does not automatically require a state construction-stormwater permit simply because it is a hard surface. Ask the municipality or appropriate conservation authority if work involves substantial disturbance, floodplains, streams or other sensitive features.
What should go on a patio or driveway permit site plan?
A labeled drawing is often more valuable than a long verbal description. Use your municipality's official application checklist first. For many outdoor projects, prepare:
- The actual municipality and parcel: street address, township/borough/city, and parcel identification if requested.
- Property boundary and streets: identify lot lines and the public street or alley; do not mistake an existing fence for a surveyed legal line.
- Existing coverage: house, other roofs, driveway, sidewalks, patios, sheds and any other surface the ordinance counts.
- Proposed work: mark the dimensions, footprint and type of new patio, driveway extension or parking pad.
- Distance to lot lines: show the relation to sidewalks, rights-of-way, easements and other site features.
- Drainage direction: note existing downspouts, slopes, inlets, proposed grading or drainage features.
- Surface calculations: keep existing coverage, removed coverage and new coverage in separate labeled totals if requested.
- Other approvals: ask about roadway access, curb cuts, sidewalk work, zoning limits, floodplains or professional design requirements.
Our residential site-plan guide contains an original illustrated example and a more detailed list of dimensions. It is a teaching aid, not a survey or permit-ready document.
A practical order of operations before paving or building
- Find the correct municipality. Verify the actual township, borough or city; a mailing address alone may be misleading.
- Describe existing conditions. Note what is grass, gravel, existing pavement and other constructed surfaces today.
- Measure the proposed new footprint. Sketch the work and calculate dimensions. Keep expansion separate from replacement or resurfacing.
- Ask about each approval type. Specifically mention zoning, stormwater management and driveway/right-of-way permission. If an attached structure or major grading is involved, ask about construction-code or additional reviews.
- Confirm design and paperwork. Ask whether the township requires a grading plan, runoff-control details, infiltration testing, survey or other professional documents.
- Get the written approval before work starts. Save the approved application, plans and any inspection requirements; don't assume a contractor's verbal assurance replaces a permit.
- Build to the approved design. If the driveway width, patio dimensions or drainage plan changes, ask whether revised approval is needed.
Our York County permit finder can point you to starting sources for six pilot communities. It does not accept permit applications, calculate official stormwater fees or guarantee approval.
Frequently asked questions
Do I need a stormwater permit for a small patio in Pennsylvania?
Maybe. There is no statewide square-foot rule that automatically settles every municipal patio application. Spring Garden Township says new impervious surfaces require a stormwater management application. Check the municipality's specific requirements for your project, even if the patio has no roof or walls.
Do I need a permit to widen my driveway?
It depends on the jurisdiction and the work. West Manchester explicitly lists driveway widening among its zoning-permit examples, and the City of York includes driveways in its zoning application route. Widening near the street may also raise access or right-of-way questions.
Is replacing an existing driveway the same as adding impervious surface?
Not necessarily. A like-for-like replacement may leave the footprint unchanged, but permit requirements may still apply. West Manchester lists repaving or replacing an existing driveway under zoning permits, while identifying seal-coating as permit-exempt. Ask how the existing and proposed conditions are classified.
Are gravel driveways or permeable pavers considered impervious?
Classification varies by local ordinance and installation details. West Manchester's published description includes non-vegetative areas, while other municipalities may have technical criteria for engineered permeable paving. Do not assume that a material labeled “permeable” eliminates zoning, stormwater or access review.
How many square feet is a 12-by-20-foot patio?
It is 240 square feet (12 × 20). Whether all of that area is assessed as new impervious coverage depends on the existing ground surface and local rules. Use the calculator above for other rectangular footprints.
Does Pennsylvania charge one stormwater fee for all patios?
No. West Manchester currently posts a $1-per-square-foot fee for new impervious area under its municipal policy, but that is not a statewide price. Other jurisdictions have different requirements and fees. Verify rates and any reductions or exceptions with the local office.
Do I need a site plan for a driveway extension?
Often a local application requests one. Springettsbury's FAQ specifically lists driveway dimensions, lot lines and easements in residential site-plan information, while West Manchester publishes site-plan requirements for zoning permits. Use the exact current form for the property municipality.
Can I direct patio runoff onto a neighbor's property?
Do not assume that a new concentrated flow is acceptable. Ask the municipal stormwater office whether the proposed grading and drainage location comply with local rules; consider engineering and legal guidance when property disputes, flooding or damage may be involved.
What if I already poured concrete without a permit?
Contact the responsible municipality and explain the existing dimensions, location and drainage conditions. Ask about any after-the-fact application and whether plans, inspections, correction work or fees are necessary. Do not assume that an informational website can authorize an existing installation.
Official government sources and editorial notes
The primary sources below support the Pennsylvania framework and the municipality-specific examples. These sources are starting points, not permits; ordinances, fee schedules and application procedures can change. Confirm current requirements with the official responsible for your particular lot.
- Pennsylvania DEP — Act 167 stormwater management framework ↗
- Spring Garden Township — zoning, building and stormwater application information ↗
- West Manchester Township — zoning permits, impervious area and posted fee ↗
- Springettsbury Township — residential permit FAQ and site-plan details ↗
- Springettsbury Township — stormwater management resources ↗
- City of York — online zoning and stormwater plan applications ↗
- City of York — municipal stormwater program ↗
- Pennsylvania DEP — homeowner runoff and stormwater practices ↗
- Pennsylvania DEP — construction stormwater and Chapter 102 program ↗