Snohomish · King · Skagit · Pierce
Grading, Drainage & Retaining Walls
Retaining walls, RV and equipment pads, and drainage correction that actually moves water away from the structure.
Grading, Drainage & Retaining Walls
In the Pacific Northwest, drainage is the difference between a property that holds up and one that quietly destroys itself. Water that sits against a foundation, pools in a yard, or runs unchecked down a slope causes more expensive damage than almost anything else on a residential site.
Grading shapes the ground so water leaves. Drainage gives it somewhere to go. Retaining walls hold back the ground you had to cut into to make either of those work. They are three parts of the same problem, and solving one without the others rarely lasts.
Retaining walls in particular are where corners get cut. A wall without proper base preparation, drainage behind it and reinforcement at height will lean, bulge and eventually fail — usually four or five wet seasons in, long after the crew that built it has moved on.
Worth Knowing
Most Washington jurisdictions require an engineered design and a permit for retaining walls over four feet, measured from the bottom of the footing rather than from finished grade. That threshold is a genuine cost cliff, and a wall quoted without accounting for it is usually a wall quoted wrong.
The Process
How a Grading & Drainage Job Runs
Water problems get diagnosed before they get dug. Moving dirt without understanding where the water goes just relocates the problem.
Site Assessment & Water Tracing
We walk the property, ideally when it is wet, and trace where water arrives, sits and leaves. Downspouts, neighbouring lots and road runoff are as often the cause as the ground itself.
Design & Elevations
Grades, wall heights and drain runs get planned against real elevations. Where a wall exceeds the engineering threshold we tell you up front rather than after the quote is signed.
Excavation & Base Preparation
Cut to depth, then base rock placed and compacted in lifts. On walls, the base and the embedment below grade are what keep it standing — not the block.
Build, Drainage & Backfill
Wall built with drain rock, filter fabric and perforated pipe behind it, geogrid layered in where height requires. Finished grade shaped so surface water runs away from every structure.
Scope
What's Included
From a single problem corner of a yard to a full site regrade with structural walls.
Retaining Walls
Block, boulder and rockery walls built with proper base, drainage and reinforcement.
French Drains & Footing Drains
Perforated pipe in drain rock with filter fabric, routed to a real outlet rather than a hopeful one.
Rough & Finish Grading
Site shaped to positive drainage with slope away from every structure.
RV & Equipment Pads
Compacted gravel pads built to carry load without rutting or sinking in winter.
Yard Drainage Correction
Standing water, saturated lawn and soggy low spots diagnosed and drained.
Erosion Control
Slope stabilisation and runoff management on sites that are actively losing ground.
Why Us
Why DirtRaptor for Grading & Drainage
Owner On The Machine
You talk to the person doing the work, not a salesperson who has never seen your site.
Arborist-Led Tree Work
Trees and dirt work handled by one company on one mobilisation — rare in this trade.
Our Own Trucks
Haul-off is not a marked-up subcontractor line. It is a truck we own and a schedule we control.
Since 2019
Years of Pacific Northwest ground, wet seasons, and county permit desks.
Honest Exclusions
Rock, groundwater and buried debris are excluded in writing, not discovered as a surprise invoice.
Free On-Site Quotes
A real number from a real site walk, not a range guessed over the phone.
Pricing
What Drives Grading & Wall Cost
Retaining walls are quoted by face square foot, but they do not cost linearly by square foot. Height is the reason.
Wall Height
Cost per face foot climbs sharply with height. Excavation behind the wall grows faster than the face area, geogrid reinforcement kicks in, embedment deepens, and around four feet an engineering stamp and permit are typically triggered. That is a cliff, not a slope.
Access & Material Movement
Block is heavy. A machine that can reach the wall line versus wheelbarrowing block through a side gate is easily double the labour on an identical wall.
Drainage & Base Requirements
Drain rock, filter fabric, pipe and the depth of compacted base are what make a wall last. They are also the first things a cheap quote leaves out.
The fastest route to an accurate number is a site walk. Quotes are free and there is no obligation.
Get My Free QuoteQuestions
Frequently Asked Questions
How much does a retaining wall cost per foot?
+
Face square foot is the usual unit, but cost per foot rises steeply with height because the work behind the wall grows faster than the wall itself. A two-foot garden wall and a five-foot structural wall are different trades. Site access and drainage requirements move it further.
Do I need a permit for a retaining wall in Washington?
+
Generally yes above four feet, measured from the bottom of the footing rather than finished grade — which catches people out. Engineered drawings are typically required at that point too. Lower walls near property lines, slopes or critical areas can also require review.
Why do retaining walls fail?
+
Almost always drainage or base preparation. Water builds up behind a wall with nowhere to go and the pressure pushes it out, or the base was never compacted properly and it settles unevenly. Both are invisible once the wall is built, which is exactly why they get skipped.
Can you fix standing water in my yard?
+
Usually. The first step is finding where the water is actually coming from — downspouts, a neighbouring property, road runoff or a high water table all present as the same soggy lawn but need different solutions. We assess before we quote.
How long does a retaining wall take to build?
+
A short accessible garden wall can be a couple of days. A taller engineered wall with drainage, geogrid and difficult access runs considerably longer. Base preparation takes more time than most people expect, and it is not the part to rush.
Question not answered here? Send us the details and we will come back to you.
Often Booked Together
Related Services
Combining scopes on one mobilisation is almost always cheaper than booking them separately.
Excavation Contractor
Foundation pits, footings, trenching, utilities, construction roads and building pads — dug to spec, inspected, and signed off.
Hauling & Dump Truck Service
Own trucks, own schedule. Spoil hauled off, material delivered, bins dropped — without waiting on a subcontractor.
Land Clearing
Raw and wooded lots made buildable. Brush, thinning, stumps and access handled by one crew instead of three.
Grading & Drainage Across Four Counties
Serving Snohomish, King, Skagit and Pierce County, Washington. Send photos and a rough scope and we will come back with a real number.
