French Drains & Drainage in Tacoma, WA
A crawl space that holds water until spring, a North End basement that leaks whenever November arrives, or a back yard that never drains: this site connects Tacoma and Pierce County homeowners with licensed local drainage contractors for French drains, sump pumps, basement and crawl space waterproofing, and foundation drainage.
Why Tacoma Ground Holds Water
Tacoma averages about 39 inches of rain a year, and the wet season runs close to seven months, from the second week of October into May. November alone brings nearly seven inches over roughly seventeen wet days. That much water would drain away on sand. Most of the city is built on something else: glacial till left by the last ice sheet, a foot or three of gravelly loam sitting on a hardpan so dense that soil scientists describe water as unable to move through it at any useful rate.
The result is a perched water table. Rain soaks the loose upper layer, hits the hardpan 20 to 40 inches down, and stops. From December through April the ground around a Tacoma foundation is full, and the water in it pushes sideways on crawl space walls and basement walls and upward on slabs. Wet basements in the Stadium District, wet crawl spaces in Fircrest and University Place, and back yards on the hill that stay soft until Memorial Day all trace to the same layer.
A drainage system gives that trapped water a path with less resistance than the house: a trench of clean rock and perforated pipe that collects it and carries it to daylight, a dry well, a permitted storm connection, or a sump pump. Which system, and where it goes, depends on whether the water is in the yard, against the footings, or already inside a basement or crawl space. The contractors this site connects you with do drainage as their trade.
Drainage Services for Tacoma & Pierce County
French Drain Installation
Footing, yard, and curtain drains built for till soil, with the filter fabric and clean rock Tacoma's fine glacial silt demands.
Basement & Crawl Space Waterproofing
Interior perimeter drains, sumps, membranes, and vapor barriers for below-grade spaces that fill every winter.
Sump Pump Installation
New pumps, replacements, and battery backup for the valley lots and low basements where gravity cannot do the job.
Foundation & Footing Drainage
Replacement footing drains for failed clay tile, curtain drains on hillside and bluff lots, and regrading.
Yard & Surface Drainage
Catch basins, channel drains, dry wells, and downspout tie-ins matched to till or outwash ground.
Tacoma Cost Guide
Planning ranges for every drainage job in Pierce County and the five things that move a quote up or down.
Three Kinds of Ground, Three Kinds of Water Problem
Pierce County is not one soil. Knowing which of the three you are standing on predicts what a drainage contractor will find, and it is the first thing a good one checks.
The till uplands: North End, Hilltop, Fircrest, University Place, Federal Way
The hills that make up most of Tacoma proper and the ridges around it are capped with Vashon till. This is the perched-water ground described above, and it produces the classic complaints: a basement that weeps at the wall-floor seam all winter, a crawl space with standing water, a lawn that squelches from November to April. The fix nearly always involves a pipe to an outlet, because the soil itself will not take the water.
The outwash prairie: South Tacoma, Parkland, Spanaway, Lakewood
South of the city the ice left something different: deep gravel outwash plains, the ground the Spanaway soil series is named for, described as somewhat excessively drained. Rain disappears into it. Water trouble on these lots is almost never groundwater. It is roof water and surface water arriving faster than the immediate area can absorb it, usually because of downspouts and grade, and it is often solved with a dry well and some regrading instead of a long trench.
The valley floor: Fife, Puyallup, Sumner
The Puyallup River valley is flat, low, and close to the water table year round. Basements are rare here for that reason, crawl spaces are common, and a perimeter drain has nowhere to run by gravity. Sump pumps do the work on the valley floor, and a backup pump earns its price during a November windstorm outage.
Signs the Problem Is Drainage
- Standing water in the crawl space after the first big November rain, and a vapor barrier floating on it.
- Water at the wall-floor seam of a basement, or damp spreading up from the slab edge.
- White mineral staining on concrete or brick foundation walls, left behind as water passes through.
- A lawn or bed that stays soft for days after the rain stops, or a low corner that ponds all winter.
- A sump pump that runs continuously through the wet season, or one that has quietly stopped.
- A musty, cold smell in the house that arrives with the rain and leaves in July.
- Soil or mulch washing across a driveway or down a slope toward the house.
A single wet night during a record atmospheric river can happen to any house. Water that returns every winter means the ground around the house is saturated on schedule, and each season it works a little further into the foundation. Earlier is cheaper.
Reach a Local Drainage Contractor
Describe what the water is doing and where the house is. A licensed drainage contractor who works Tacoma and Pierce County will follow up, usually the same day.
Tacoma Drainage Questions
How much does a French drain cost in Tacoma?
A yard French drain runs about $2,000–$7,000; an interior perimeter drain with a sump, the usual fix for a basement or crawl space that fills every winter, about $5,500–$14,000; a new exterior footing drain about $6,000–$15,000. Length, trench depth, and how far the water travels to an outlet set the price. The cost guide breaks each job down.
Why do so many Tacoma crawl spaces and basements get wet?
Most of Tacoma's hills sit on glacial till: a couple of feet of loose gravelly loam over a hardpan water cannot pass through. From December through April the rain perches on that hardpan a foot or two below the surface and presses on every footing and crawl space wall in its way. Add 39 inches of rain a year and a housing stock that is 64 percent pre-1980, and the water finds the seams. Foundation drainage relieves it.
Is a French drain the same thing as basement waterproofing?
A French drain is one component: a gravel-and-pipe trench that collects water and moves it elsewhere. Basement waterproofing is the whole job of keeping a below-grade space dry, which in Tacoma normally means an interior perimeter drain, a sump pump, a wall membrane, and sometimes a backup pump. The drain does most of the work.
Do I need a permit for drainage work in Tacoma?
Drainage that stays on your own property with no connection to the City's system generally does not trigger a City permit. Connecting to the City storm system or to anything at the curb requires a Stormwater Construction or Repair Permit from Environmental Services, and Tacoma Municipal Code forbids sending groundwater, yard, or roof drainage into the sanitary sewer. Outside city limits, Pierce County Planning and Public Works reviews site development. More in the FAQ.