Short answer
Usually not without approval, and in some townships not at all. Cheltenham and Upper Moreland bar fences in swales and watercourses and forbid any fence that blocks stormwater from your lot or a neighbor's. Towamencin's code bars fences in easements and basins (it mentions written consent from the easement holder, but its permit form says no fence on an easement at all), and Montgomery Township requires a signed fence easement agreement. In Abington, check the recorded plan and confirm with the township first.
Swale, easement or floodplain?
- Swale: a shallow, grassed channel shaped to carry stormwater across or along lots. Many subdivisions were graded with them along back and side lines.
- Easement: a recorded right for someone else, often the township or a utility, to use a strip of your land for drainage, sewer or access. It shows on your deed or the subdivision plan.
- Floodplain: a mapped zoning district along a creek, with its own, stricter rules.
A back-lot swale is often inside a drainage easement, so both sets of rules can apply to the same strip of grass.
What local codes say
| Municipality | Swales and stormwater | Easements |
|---|---|---|
| Cheltenham (Glenside, Elkins Park) | No fence in a floodplain, swale or watercourse; no fence may block stormwater from the site or an adjoining property | Not addressed in the fence section we read |
| Upper Moreland (Willow Grove) | Same: no fence in a floodplain, swale or other watercourse, and none that blocks stormwater flow | Fence work in the public right-of-way needs a township permit |
| Abington (Roslyn, Glenside, Willow Grove) | Pools may not sit in a swale. A fence-specific rule hasn't been confirmed in the code text we read. | A recorded-easement rule has been reported but not confirmed in the code text we read; we check with the township |
| Towamencin | — | No fence in an easement, retention or detention basin, or the street right-of-way; the code mentions the easement owner's written consent, but the permit form says no fence on an easement |
| Montgomery Township | No fence that interferes with stormwater flow, or in a floodplain or wetland | Discouraged; needs a signed fence easement agreement with the township, must be easily removable, extra fee applies |
| Hatfield | — | No fence in an easement benefiting the township without written permission |
| Lansdale Borough | No fences in the floodplain district | Failing to disclose an easement voids the fence approval |
Checked October 2026 from the cited code and permit documents. We confirm with the zoning office before every install.
Why townships are strict about this
A fence across a swale catches leaves, grass clippings and trash, and the debris turns it into a dam. Water that should move along the back of six lots backs up into one of them instead, often a neighbor's. These are not rare storms here: Ida dropped an average of 8.25 in of rain across Montgomery County in 2021. Sandy Run starts in Roslyn and Dresher, and the Pennypack runs through Upper Moreland, so much of the ground around Willow Grove and Abington drains toward small streams that rise fast.
Options when a swale crosses your backyard
- Pull your deed and the subdivision plan to see whether the swale sits inside a recorded drainage easement and who holds it.
- Run the fence along the edge of the swale instead of across it, so water keeps its path.
- Where the fence has to cross, ask whether an open style, like split rail or aluminum raised off the grade, would be approved.
- Plan a removable section or a gate where the township or utility may need access.
- Get any easement agreement or written consent in hand before materials are ordered.
We mark swales and easement lines on the plot plan we prepare for your permit, so the township sees how water will keep moving before it signs off.
Common questions
Can I fill in the swale so the fence can go straight across?
Don't change the grade without talking to the township first. The swale is usually part of the neighborhood's stormwater design, and we don't regrade swales as part of a fence job.
My neighbor's fence already crosses the swale. Can mine?
An existing fence doesn't make a new one legal. Each permit is reviewed on its own, under the current code.
Does a split-rail fence count as blocking stormwater?
Open styles let water through far better than solid panels, but whether one is allowed in a swale is the township's call. Cheltenham and Upper Moreland bar fences in swales outright.