No down payment. You pay when the project is finished.
Monday – Friday, 9:00 AM – 7:00 PM · Capitol Hill, Seattle
Drainage · Issaquah
Issaquah drainage is a different discipline from suburban drainage, and the reason is that most of the water is not yours. A property built into the flank of Cougar, Squak or Tiger sits on the route of everything moving downhill off the mountain through six months of wet weather. It arrives across a wide front rather than at a downspout, the volume is far larger than the lot generates itself, and it does not stop when the rain does. A system designed to collect water after it has reached the house is fighting something it was never sized for, which is why so many retrofit drains on these slopes are overwhelmed within a couple of seasons.
Wide paver driveway and turning apron in front of a garage on a sloped Issaquah lot
What we get called about
Issaquah is the retaining wall market on this side of the water. The city sits in a valley surrounded by mountains, and properties built into those slopes need grade held before anything else can happen. The second local factor is water arriving from above: on a hillside lot, a significant share of what you are managing did not fall on your property at all, it came down off the mountain, and drainage has to be sized for that rather than for your roof area. Third, HOA coverage here is among the densest in the region.
Worth knowing in Issaquah
The distinction between these two approaches is the whole of hillside drainage, and getting it wrong is why so much money is wasted on this side of the water.
Collection means putting a drain where the problem shows — the wet corner, the puddle by the patio, the damp against the foundation — and taking the water away from there. On a flat suburban lot managing its own rainfall, that is correct and sufficient. On a mountain flank it means your system is receiving everything the hillside sends, at whatever rate the weather chooses, after it has already spread across the ground you were trying to protect.
Interception means cutting the flow off upslope of the area you care about and routing it around, so the water never arrives. The drain sits where the topography says rather than where the symptom is, which sometimes puts it in an unintuitive place — well above the house, or along a boundary nowhere near the standing water. It is usually a shorter run, a smaller system and a considerably more reliable outcome.
The method
The sequence does not change between neighbourhoods — what changes is the ground it is applied to. Full detail on the drainage service page.
Roof, surface runoff, a neighbouring property's grade, or groundwater sitting on the till. These need different answers and guessing wastes the whole job.
A drain needs somewhere legal and physical to go — daylight at a lower point, or an approved connection. A drain that terminates in a hole is a soakaway on ground that does not soak.
Continuous fall along the whole run. A trench that dips holds water and silts up, which is the most common reason a retrofit drain stops working.
Perforated pipe bedded in clean washed rock, wrapped in geotextile so the surrounding soil cannot migrate in and clog the void.
Turf, planting or hard surface put back so the finished job does not read as a scar across the garden.
What it costs in Issaquah
Issaquah runs at the upper end of $10 to $25 per linear foot more often than the rest of this list, because the systems are larger. Interception drains have to be sized for mountain flow rather than roof area, which means bigger pipe, more rock and an outfall with real capacity. Set against that, a properly sized interception drain is usually cheaper than the alternative, which is repeatedly repairing whatever the water damages downhill.
You pay after the project is fully completed.
The estimate you sign is the price you pay.
Spread the cost with no interest.
Covers hardscape work; vegetation excluded.
Local questions
General questions about this service are on the service page. These are the ones that only come up here.
Upslope of whatever you are protecting, on the line the topography dictates rather than where the water is currently visible. That is frequently counter-intuitive — the drain may end up well above the house, along an upper boundary, nowhere near the wet patch you called about. The logic is that you are cutting a flow path rather than emptying a puddle. We walk the lot in the wet if we possibly can, because the route water takes across a hillside is obvious in January and largely invisible in July, and getting the alignment right is most of what makes these systems work.
Frequently, and it is worth trying before assuming the wall has to come down. Most wall movement on an Issaquah slope is caused by water pressure behind the structure rather than by the wall being undersized for the soil — saturated ground is heavier and pushes considerably harder than drained ground. Retrofitting drainage behind an existing wall, or intercepting flow above it so the ground behind it stops saturating, removes the load that is causing the movement. Whether that is enough depends on how far the wall has already gone. We will tell you honestly when it is past the point where drainage alone will save it.
Yes, and it is close to the opposite problem from the hillsides above it. The valley floor around the creek is flat, alluvial and close to a high water table, so a trench there runs out of useful depth quickly and has very little fall to work with. Where the hillside problem is too much water arriving too fast, the valley problem is water that has nowhere to go once collected. Proximity to a creek corridor may also bring critical area rules into play, so on those lots we establish what applies to the parcel before designing a discharge.
Two things, and both genuinely help. First, look at where your downspouts discharge — roof water arriving in a single spot on a slope is a large concentrated volume, and extending a discharge well clear of the building sometimes fixes what looked like a bigger problem. Second, if you can, take photographs during a sustained wet spell showing where water runs and where it stands. That is the single most useful thing a homeowner can hand us, because it captures the flow paths that a dry-weather site visit simply cannot show.
Serving Issaquah and surrounding neighbourhoods
Olde Town Issaquah · Issaquah Highlands · Talus · Squak Mountain · Cougar Mountain · Providence Point · Klahanie · Sammamish Plateau edge
98027 · 98029
Recent work
Retaining WallsView full sizeOne course of tan split-face block turns a soft slope into a level bed and a level lawn. The planting sits above the wall instead of sliding down it, which is the entire reason the wall is there.
Paver PatioView full sizeThree sizes and two colours laid in a random ashlar pattern. Blending from several pallets as you work is what stops a batch difference turning up later as a stripe across the patio.
Driveway PavingView full sizeThe apron takes the worst of the turning load, which is why it is where a driveway fails first. Laid on a full vehicle-rated base with a banded border holding the edge.
We come out, look at the ground, and put a fixed written price together. No deposit, and it does not change once agreed.
Free estimate
Three minutes on the form. We reply during office hours, Monday – Friday, 9:00 AM – 7:00 PM, and we come out and look at the site before quoting anything.
Or call (425) 533-9734
Thank you — we have your details. We reply during office hours, Monday – Friday, 9:00 AM – 7:00 PM. If it is urgent, call (425) 533-9734.
