Water with nowhere to go but the street?
When the yard is wet, the curb looks like the obvious exit. In Prosper a curb core is the fallback, allowed only when water can’t leave over the surface. Clay Plano Drainage Company installs French drains and outlets in Prosper in that order.
So the first question on every job is whether the yard can drain over the surface.
What Prosper’s curb coring rules say
Prosper’s curb coring guidelines are unusually specific. A core requires a right-of-way permit, and it’s allowed only where surface flow cannot be accommodated.
| Rule | What it means for your drain |
|---|---|
| Monolithic 6-inch curbs only | Not every curb can be cored |
| One core per lot, 3 inches max | Every line that goes to the street shares one small opening |
| Perpendicular crossing of the right-of-way | The line runs straight to the curb, not at an angle |
| Sidewalk bores backfilled with flowable fill | The walk is bored under, not broken, and won’t settle |
| 2 feet clear of meters, laterals, mailboxes and lights | The core’s spot is set by what’s already in the parkway |
| Inspection booked 48 hours ahead | The town sees the work before it’s closed |
Arranging the permit and booking the inspection are on us, not you.
Surface first, curb second
Because the core is a last resort, we look hard at the surface options first. They are often simpler anyway.
- An emitter in the front lawn lifts open to release water over the grass during a storm and drops shut afterward.
- Regrading can restore a front slope that sends water to the gutter on its own.
- A swale along a side yard carries sheet flow to the street without any pipe at the curb.
Only when none of those can take the water does a core go on the plan. For a side-by-side look at every exit, see our outlet guide.
Sharing a 3-inch opening
One core of 3 inches or less is a real limit. Roof water from several downspouts plus a yard French drain can be more than that pipe should carry in a heavy storm.
When the flows add up, we split them: some lines to emitters in the lawn, one to the core. That way no single outlet is asked to do everything, and the lawn emitters keep working even if the core line is ever slowed by leaves at the gutter. Cleanouts at each junction let us flush any branch on its own.
Sloping clay in Prosper
Parts of Prosper are mapped on Heiden clay, on 3 to 5 percent slopes marked as eroded. It’s a heavy clay, as prone to swelling as the Houston Black under east Prosper, and it sheds water slowly.
On a slope, that combination works against you twice. Rain can’t soak in fast, so it runs; and running water on bare clay cuts ruts and carries soil toward the curb.
- Break long slopes with shallow swales that catch water before it gathers speed.
- Slow the outlet with rock or a spreader where a line lets go.
- Build for clay. A French drain here needs a generous stone zone and fabric to keep fines out, the build described in our page on drains for heavy clay.
Along the foundation
A slab on swelling clay shifts when the soil under one edge is soaked and the soil under another is dry. Foundation drainage starts with the roof: we pipe downspouts away and keep the beds sloping outward, and the guide to foundation moisture in clay soil covers why.
Prosper’s neighbors
Prosper runs from US 380 north, with Preston Road and the Dallas North Tollway carrying traffic through it. Its neighbors handle drainage their own way:
- Frisco treats work inside a recorded easement, not just at the street, as permitted right-of-way work.
- McKinney wants finished grade to fall at least 6 inches in the first 10 feet from a building.
- The Colony lets water cross between lots only through a drainage easement covering every property on its path.
How a Prosper job comes together
We decide the outlet before the route, and on a Prosper lot that means checking the surface options before the curb.
- Source. Roof, slope, sprinkler or soaked clay, each traced on the visit.
- Outlet. Surface where it works; a single permitted core where it doesn’t.
- Fall. Taken with a level from the soggy spot down to the exit, so the line never holds water.
- Test and restore. Water through the system before backfill, the town’s inspection where a core is involved, then sod and sprinklers back.
Before you send photos
A few pictures from the street side tell us most of what we need to know about a Prosper outlet:
- The curb in front of the lot, so we can see whether it’s the monolithic 6-inch type the guidelines require.
- The parkway: meters, mailbox, lights and any cleanouts already there, since the core has to keep 2 feet from them.
- The sidewalk, if there is one, because a line to the curb would be bored beneath it.
- A storm video of the front yard, showing whether water already reaches the gutter over the grass.
Spring and fall are when these yards show their problems; on the nearby Plano record, May and October are the wettest months.
One more option
Where one wet low spot is the whole problem, a catch basin may be all it takes; the guide to French drain vs catch basin helps you compare.