The short answer
Water enters the stone, reaches the perforated pipe, and should travel by gravity to a lower, appropriate discharge point on the property — or into another exterior drainage component that already has a working exit.
What counts as “appropriate” is a property-and-jurisdiction question. This page does not invent Rockford street, storm-sewer, or neighbor-discharge rules. We do not tell homeowners from a website to dump water onto someone else’s lot, a public street, or a storm drain.
French drain installation is the service page for how the trench is built. This page is about the exit.
Why the outlet matters as much as the trench
The trench is the collector. The outlet is the reason the collector can empty.
If the pipe ends uphill of the wet area, water will not leave. If the outlet sits in another low spot, you moved the swamp a few yards. If landscape work buried or crushed the exit, a drain that used to work can fail without the trench itself collapsing.
That is why a site visit looks at discharge as carefully as it looks at where you want the lawn to dry. Yard drainage is the broader plan that includes that exit.
Conceptual ways the water can leave
On many residential lots the pipe can run downhill to a lower point that will not recreate the original wet area — a place water can spread or continue in an existing exterior drain without soaking the house or a neighbor’s yard.
Sometimes the French drain ties into another exterior piece already in the plan: a solid run after the perforated section, a basin line, a downspout drain that already has a legal exit. That is a design choice on the property, not a default kit.
Other lawful arrangements exist. They are not listed here as a menu of street connections or municipal loopholes. If a permit or an approved connection is required, that is verified for that job.
What happens when a French drain has nowhere to discharge?
The stone saturates. The pipe holds water. The lawn over the trench stays wet, or the original swamp never leaves. People then assume the drain is “clogged” when the honest problem is that it never had an exit — or the exit failed.
An existing drain that used to empty and no longer does is a repair question: outlet obstruction, damaged pipe, settlement, or a landscape change that buried the discharge. Standing water over a known drain route is a reason to inspect. It is not, by itself, proof of the cause.
Signs your French drain may need repair covers that pattern without treating every wet yard as a clog.
Related drainage pages
Installation, repair, and the broader yard plan all assume the water has somewhere to go.