Concrete Retaining Walls in Sammamish, WA

Retaining walls in Sammamish: what to know

Measured from the footing bottom to the top, a wall of four feet or less stays out of the building permit track while nothing surcharges it. Fill behind the wall, a structure within reach of it, or a vehicle loading the top moves the wall into review even when it is short. The clearing and grading rules also apply if the wall sits in a cut, and a wall in a critical area or its buffer cannot be exempted except on publicly owned land.

Drainage needs a legal outlet too. Water collected behind a wall should leave the lot at a point the lot can take, not onto a neighbor’s slope or into the street. Where a wall drain may discharge is confirmed with city staff before the footing is placed, so the outlet is settled before any excavation starts.

Permits and rules in Sammamish

We check the wall height, the load behind it, and its position against the property line before we quote. A wall in a critical area or its buffer follows the critical area permit rule, and the drain outlet is confirmed in the same review. City staff confirm how the wall is treated for your address.

Sammamish’s clearing and grading page says a Clearing and Grading Permit or Site Development Permit is required before site work unless SMC 16.15.050 exempts the work. It caps cut and fill slopes at 2 horizontal to 1 vertical unless the Director approves, and it says work within critical areas or their buffers cannot be exempted, except on publicly owned land. Rules change, so we confirm the current requirements with the city before we start.

How we approach it

Take the wall height from footing bottom to top
Record any fill, structure, or vehicle load behind the wall
Locate the wall against the property line and any easement
Confirm the drain outlet with city staff before footings are placed

For the full process, see our Retaining Walls page.

Building in the cold months? See our guide to winter concrete pours.

Our retaining walls work, serving Sammamish

Examples of our work. We build retaining walls in Sammamish and the cities around it. See all of our work

Questions from Sammamish homeowners

Does the four-foot wall exemption apply when a Sammamish driveway sits behind the wall?

No. A driveway, building, or other load behind a wall is a surcharge, and a surcharge takes the wall out of the residential exemption at any height. We record that load before the footing is set, so the wall is reviewed with it in place.

Does fill behind a Sammamish wall change the outcome?

Yes. A surcharge takes a wall out of the residential exemption, so fill, a structure, or a driveway behind the wall is recorded before design.

What happens to the water collected behind a Sammamish wall?

It has to leave the lot at a point the lot can take, not onto a neighbor’s slope or the street. The outlet is confirmed with city staff before the footing is placed, because the wall and its drain are reviewed together.