French Drains & Drainage Systems in Poulsbo, WA

Drainage & French drains in Poulsbo: what to know

Start with the discharge, then work back to the trench. On a Poulsbo lot the outlet decides where the water lands, how far it travels, and whether a public connection or a shoreline review is involved. A May 2022 council memo ties city stormwater design to the 2019 Stormwater Management Manual for Western Washington, effective July 1, 2022. The memo does not state design thresholds, so we confirm which ones apply to your parcel and do not use the superseded 2010 ordinance figures.

Interception runs sit above the saturated ground, so the flow is caught before it spreads across the lawn. Roof water runs in its own solid line with a separate exit, so it never fills the perforated run. A trench that reaches a street right-of-way or a utility easement needs a public property construction permit under PMC 12.08, approved by the city engineer. On an Alderwood or Kitsap lot, trench depth is set against the seasonal water table window before any cutting starts.

Permits and rules in Poulsbo

A drain can raise grading and right-of-way questions, and the discharge point decides which ones apply. We check whether the trench reaches a street right-of-way, whether the work changes grade by more than four feet, and whether the earthwork counts toward the 50 cubic yard figure in PMC 15.40. The governing review is identified before any digging, and we confirm each requirement with city staff before the quote is issued.

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

How we approach it

Choose the discharge point before sizing the trench
Keep the interception run above the saturated ground
Give roof water its own solid line and exit
Confirm any right-of-way permit before the trench is cut

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

Questions from Poulsbo homeowners

Which discharge points can a Poulsbo French drain use?

A discharge on your own parcel, or a storm connection that city staff confirm for your address. We do not route flow onto the street or onto a neighbor’s frontage.

Does a French drain in Poulsbo fall under PMC 15.40?

It can, if the earthwork passes the chapter’s lines: more than 50 cubic yards within a 12-month period, or a grade change over four feet. Cut and fill are not netted against each other, and smaller work falls under an exemption that carries slope and stream limits.

Can a drain help a soggy yard in Poulsbo near the shoreline?

It may. A drain placed between the lawn and the groundwater can relieve wet ground, but we measure the groundwater depth first and do not promise a result from a guess. PMC 16.08 review comes first whenever the trench is close to the water.