Every property sheds water somewhere. The question is whether that path was designed — or whether it’s the route water found on its own.
After a heavy storm the evidence is easy to read: a saturated seam of turf running downhill from a downspout, a rim of silt where water paused at the edge of a terrace, a planting bed that never quite dries out. These aren’t plumbing failures. They’re grading, soil, hardscape, and roof area interacting in ways nobody planned for.
Why older Main Line properties are prone to it. Much of the housing stock in Radnor, Villanova, Bryn Mawr, and Gladwyne predates modern stormwater standards. Homes were sited high, gutters discharged near the foundation, and the surrounding acreage absorbed the rest. Then came the additions, the pool, the expanded terrace, the wider driveway — each converting pervious ground to impervious surface. Add the region’s clay-heavy, construction-compacted subsoil, and water that would percolate in twenty minutes elsewhere sits for hours here.
The reactive fix relocates the problem. Installing a drain where the water is often just moves it twenty feet downhill — sometimes onto a neighbor’s property, which is a more expensive conversation. A designed solution starts with the watershed instead of the symptom: where water enters, how much impervious surface is contributing, whether soils will accept infiltration, and where the system can legally and sustainably discharge. Township ordinances across Lower Merion, Radnor, and Tredyffrin have tightened considerably on that last point.
Matching the solution to the condition is most of the work — French drains, catch basins, buried downspout collection, drywells, rain gardens, dry creek beds, permeable paving, or sometimes just correct regrading and no pipe at all. Done well, none of it announces itself: basins set flush and screened in planting, conveyance that reads as a garden feature in dry weather.
Maintenance is what keeps it working. Basin sumps silt in, outfalls get obscured, drywells lose capacity, connections separate. None of it is visible until the storm that overwhelms the compromised system. Seasonal inspection costs a fraction of a mid-storm emergency.
What “premier” means on this kind of work. Responsive — when a storm exposes a problem, the timeline that matters is the one before the next storm. Capable — drainage sits between civil engineering, horticulture, and hardscape, and a crew that can trench but can’t rebuild the terrace it lifted leaves you with a solved problem inside a diminished landscape. Proactive — the best drainage consultation happens before the pool goes in, not after.
If you’ve seen standing water this season, photographs taken during and just after the rain are genuinely useful diagnostic information. Terren Landscapes has designed and built landscapes on the Main Line since 1983; stormwater is part of how we approach every property, not a separate service line.
