French Drains & Drainage Systems in Lake Forest Park, WA

Drainage & French drains in Lake Forest Park: what to know

Set into the hillside, a curtain drain stops seepage before it reaches the lawn or the house. Its trench drops at a constant rate, and the gravel is placed so water keeps moving instead of pooling. A French drain at the lower end collects what gets past the curtain and carries it onward to the outlet.

Roof water runs in solid pipe to a discharge point, kept apart from the perforated system. The outlet is picked from three options: ground able to take the volume, a city storm connection that will accept it, or a low spot on the parcel that will not flood a neighbor. Drainage that leaves the site or ties into the city network is a major clearing and grading item, so the outlet is listed on the scope before the trench is staked.

Permits and rules in Lake Forest Park

Before quoting, we confirm which office runs the review, whether frontage rules apply through the right-of-way use application, and whether the drain falls under the major clearing and grading track. The city’s stormwater pollution prevention checklist refers to the King County Surface Water Design Manual, Chapter 2, so the route is checked against that reference as well. Every review is tracked on the scope with its current status.

Rules change and vary by parcel, so we confirm the current requirements with the city before we start.

How we approach it

Find where seepage first enters the lot
Cut the curtain drain on a steady hillside fall
Carry downspout water in solid line to its exit
Name the controlling frontage review before trenching

For the full process, see our Drainage Systems & French Drains page.

Questions from Lake Forest Park homeowners

What makes a Lake Forest Park drain outlet acceptable?

Ground that can absorb the water, a city storm connection that takes it, or a low spot that spares the neighbors. Adjoining lots and the street never count as outlets. A drain that leaves the site or ties into the city network also counts toward the major clearing and grading track.

Which Lake Forest Park drain work reaches the clearing and grading tracks?

A cut that moves more than 25 cubic yards reaches the minor track, and 50 or more reaches the major track. Drainage leaving the site or tying into the city network is on the major track, and the city planning department gives the controlling answer before excavation starts.

When is a drain the right answer for a soggy Lake Forest Park hillside?

Usually when seepage from the slope keeps the lawn saturated. We trace the entry point first, then place the line where it can intercept that inflow. A drain set at the wrong point wastes the work.