What Drainage Work Costs in Tacoma, WA
Planning ranges for French drains, sumps, waterproofing, and foundation drainage in Pierce County, what moves them, and how to tell a complete quote from a thin one.
The Short Version
These are planning ranges for the Tacoma area with the reasoning behind each one; a quote needs someone standing on the property.
A yard French drain in Tacoma runs about $2,000 to $7,000; an interior perimeter drain with a sump pump about $5,500 to $14,000; a new exterior footing drain about $6,000 to $15,000. Length, trench depth through hardpan, and where the water can exit set the price more than anything else.
| Job | Planning range | When it applies |
|---|---|---|
| Downspout extension or tie-in | about $300 – $1,800 | Roof water dumping at the foundation; the first thing to check |
| Dry well | about $1,500 – $4,500 | Outwash soil in South Tacoma, Parkland, Spanaway, Lakewood |
| Yard French drain | about $2,000 – $7,000 | Ponding lawn or bed on a till lot |
| Crawl space drain and sump | about $3,500 – $9,000 | Standing water under a post-war house |
| Curtain drain | about $3,500 – $10,000 | Hillside or bluff lot, water arriving from uphill |
| Interior perimeter drain and sump | about $5,500 – $14,000 | Wet basement; the standard fix on a finished basement |
| Exterior footing drain | about $6,000 – $15,000+ | Failed clay tile on a pre-1950 house, yard accessible |
| Sump pump, install or replace | about $1,000 – $3,500 | Basin and pump; battery backup adds about $600 – $1,500 |
| Full waterproofing system | about $9,000 – $20,000+ | Perimeter drain, sump, backup, membrane together |
Planning ranges, not quotes. The three local businesses that rank for these searches publish no prices at all, and the per-foot figures on national estimator sites cluster around $50 to $66 a foot for interior drains and roughly double that for exterior foundation work; the ranges above are built from those rates and typical Tacoma run lengths. Your number comes from someone standing on your property.
What Moves the Number in Tacoma
Which soil the house is on
On the outwash gravel south of the city, a dry well and some regrading can solve a problem that on a till lot in the North End needs a hundred feet of trench to an outlet. Same puddle, and the till version costs three or four times as much. The soil is the first thing an assessment establishes.
Where the water can exit
A hillside lot that falls to daylight is the cheap case. A flat valley lot in Fife or Sumner needs a sump and a backup. A storm-system tie-in inside city limits adds an Environmental Services permit and the connection work at the curb. The outlet frequently matters more than the length of the drain.
Crawl space or basement
A perimeter drain trenched into a crawl space floor is shallower and faster than one cut through a basement slab, which is why the crawl space row in the table sits well below the basement row. The majority of Tacoma houses built after the war are on crawl spaces, so this is the more common job.
Length, depth, and hardpan
Drainage is priced heavily per foot, and digging through Tacoma's compacted till is slower than digging sand. A full footing drain around a deep North End basement is a different project from a 30-foot run across a lawn.
Access and what is on top
The older neighborhoods have narrow lots, alley access, mature trees, and a century of hardscape. A trench under open lawn is cheap to dig and restore; the same trench under a driveway, a patio, or the roots of a ninety-year-old maple is hand work and expensive to put back. Interior systems avoid all of it, which is one reason they win on finished basements.
How to Read a Quote
- It names the outlet. Daylight, dry well, storm connection, or sump. A quote that leaves this out has not finished the design.
- It rules out the cheap causes. A contractor who checks downspouts and grade before proposing a $12,000 excavation is solving your problem rather than filling a schedule.
- It specifies materials. Filter fabric, washed drain rock, pipe diameter, and slope. In Tacoma's silty till these decide whether the drain lasts thirty years or three.
- It says whether a permit applies. Storm tie-ins, curb work, and work on regulated slopes can need one from the City or from Pierce County. A bid that skips it is incomplete rather than cheap.
- It holds up to a second opinion. On anything over a few thousand dollars, a second assessment is worth the week it takes.