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Princeton Excavation

Subsurface Drainage

French Drain Installation

Princeton Excavation installs exterior French drains for yards that stay wet. We machine-trench the run, line it with filter fabric, bed perforated pipe in washed stone on a consistent positive pitch, and carry the water to a real outlet: daylight where the grade allows, a dry well where it doesn't. Built for central New Jersey clay, not sandy-soil textbook conditions.

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What's in the trench

What's in the trench

A French drain is a simple system with no optional parts. Skip one and the drain has a short life. Here's what goes into every run we build.

Filter Fabric and Washed Stone

Geotextile fabric lines the trench and wraps the stone envelope, keeping fine clay particles out. Washed gravel, not crusher run, surrounds the pipe so water moves instead of sitting in packed fines.

Perforated Pipe on Laser Pitch

We set trench bottoms with laser grade control so the perforated pipe holds continuous positive pitch end to end. No bellies, no flat spots where water and silt collect.

An Outlet That Goes Somewhere

Collected water has to leave. We daylight the outlet downslope when the grade gives us the fall, or size and dig a dry well when it doesn't. A drain that dead-ends is just a buried puddle.

Why hand-dug drains silt up

Most failed French drains we open up were built the same way: a weekend trench, gravel dumped straight against the soil, no fabric. In our clay-heavy soils, fines migrate into the stone within a few seasons and the whole trench packs solid. The fabric isn't an upgrade. It's the part that decides whether the drain lasts three years or decades.

  • Where we work

    The other local factor is volume. A seasonal high water table plus roof runoff concentrated at downspouts puts more water into a Mercer County yard than clay can absorb. We size the pipe and stone for that load, keep downspouts on their own solid pipe rather than dumping into the French drain, and call in the NJ One Call (811) markout before trenching near any utility runs.

How a job goes

From the first call to a clean handover

  1. 1. Site Walk

    We come look at the property by appointment, check the access and any constraints, and go over your plans or what you have in mind.

  2. 2. Marking & Layout

    We set the layout on the ground with laser accuracy. Depths, lines, and elevations are marked before anything gets dug.

  3. 3. The Work

    We bring the right machine for the access, lay ground protection where it's needed, and keep the mess around lawns, trees, and hardscape to a minimum.

  4. 4. Clean Handover

    You're left with a site that's ready to go and a yard that's still in one piece, set up for whatever's next.

Frequently Asked Questions

No. We build exterior and yard systems: the trench-and-pipe runs that intercept water outside before it reaches the house. Interior perimeter systems under a basement slab are waterproofing-contractor work, and we'll say so if that's what your situation calls for.

Princeton, Hopewell Township, Montgomery & Skillman, and surrounding Mercer and Somerset County, NJ.

Wet yard every spring? Let's walk the trench line before the next rain.

Owner-operated and by appointment. Tell us about your project and we'll walk the site with you.

Request a Site Visit
Call (609) 438-8064Site Visit