French Drains & Drainage Systems in Spanaway, WA

Drainage & French drains in Spanaway: what to know

On this outwash plain, a French drain rarely has to chase a distant storm line. The county’s stormwater action plan for the Spanaway Lake watershed says nearly all stormwater there already soaks into the ground, so an infiltration outlet is common: a drain-rock trench, a dry well, or a spread-out dispersion area. The question is whether your soil, neighbors, and water table can take the added volume.

When a yard stays wet, look for the cause before the trench. Soil compacted or filled during subdivision grading, a roof that sends all its water to one corner, and low pockets near the lake, marsh, or creeks can each hold water on ground that otherwise drains. A French drain suits only some of those fixes.

Permits and rules in Spanaway

Drainage work can touch several county rules. Pierce County lists altering a stormwater drainage system or drainage course, grading within 25 feet of a ditch or creek, moving 50 cubic yards or more, and creating new impervious surface among its site development triggers, and the county counts gravel as impervious. Water cannot be pushed onto a neighbor or into a sanitary sewer. We look up where Pierce County allows water from your lot to go before we trench.

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

How we approach it

Trace where water enters your lot and where it can legally leave
Judge soil, groundwater signs, and neighbors before choosing an infiltration outlet
Call for locates and find septic lines before trenching
Keep drains and downspout lines out of septic reserve areas

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

Questions from Spanaway homeowners

Where can a Spanaway French drain discharge?

Usually onto your own lot: an infiltration trench, a dry well, or a dispersion area, if the soil and water table allow. The county also has rules for drainage courses, and water cannot go onto a neighbor. We settle the outlet before we dig.

Can I run my downspouts into a drain at the back of my Spanaway lot?

Often, through a solid tightline to an outlet that can take the roof’s water, not into perforated pipe. Roof water in one spot is a common reason gravelly yards still get wet. The health department also says to keep roof drains away from a septic drainfield.

My Spanaway yard floods near the creek or marsh. Will a drain help?

Maybe not. Near the lake, marsh, or creeks the water table itself can rise in winter, and a drain with nowhere lower to go will not fix that. We look at the whole lot and tell you if the ground is simply wet.