French Drains & Drainage Systems in Woodinville, WA

Drainage & French drains in Woodinville: what to know

Drainage that moves a larger volume of earth, or that changes how water leaves a lot, is measured against the site development rules. Earth movement of 25 cubic yards or more on an R-1 through R-8 lot falls outside item (a) of the exemption, so the site development permit rules apply. A trench for utilities that needs a right-of-way permit is exempt under item (c), and that right-of-way permit is confirmed with the city.

Layout is the practical part. A curtain drain on the uphill side intercepts water before it saturates the lawn, and a tightline carries downspout water to the same outlet in solid pipe. We keep the perforated run separate from the roof lines, grade the trench to a steady fall, and discharge the water onto ground that can take it. Stormwater requirements for each lot are confirmed for your address before the outlet is designed.

Permits and rules in Woodinville

Drainage work is measured against the site development exemption by the volume of earth moved and the disturbed area. We confirm the requirement before we quote. A trench for utilities that needs a right-of-way permit is exempt from the site development permit under item (c), and the outlet, along with any tie-in to a storm line, is confirmed with the city before we dig.

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

How we approach it

Find the source of the water before choosing the drain route
Set the interception drain on the uphill side of the wet ground
Run roof lines in their own non-perforated pipe, off the drain run
Confirm the outlet and any storm connection with the city first

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

Questions from Woodinville homeowners

Which outlet works best for a Woodinville French drain?

Your own ground, if the soil drains well enough to take the flow, or a storm line, if the city approves that tie-in. Water should not head for the street, the sidewalk, or a neighbor’s lot, so we fix the outlet before the trench is cut.

Does a Woodinville drainage project need an engineer?

The code sections checked for this page do not say when a drain needs engineered plans, so we confirm that with the city for your lot. A drain that moves 25 cubic yards or more of earth in an R-1 through R-8 zone falls outside item (a) of the exemption, so the site development permit rules apply.

My Woodinville yard floods near a hillside. Can a drain fix it?

Sometimes. A drain above the yard can intercept water arriving from higher ground. The slope may warrant a closer survey, so we measure the grade and the soil first and promise nothing until then.