Crawl Space Sump Pump Installation and Repair in Seattle

Sources

The rain normal and soil figures are this site's published climate and housing dataset values; the perched-water pattern is the Seattle Landslide Study's; the peat, discharge, side sewer and electrical permit rules are the City of Seattle's; which cities run their own electrical permits is L&I's list; the owner exemption from contractor registration and the electrical contractor license are Washington law; the sump lid guidance is the U.S. Department of Energy's Building America Solution Center; the pump service life is InterNACHI's chart. Installed ranges are this site's modeled estimates; see the cost methodology.

1. NOAA National Centers for Environmental Information, U.S. Climate Normals (1991–2020) — Annual/Seasonal and Monthly (normals-annualseasonal-1991-2020, normals-monthly-1991-2020) Open dataset Checked November 10, 2026

   Every precipitation figure in the Seattle-metro climate and housing dataset: annual and monthly precipitation normals, the October–March total summed from the monthly normals, the average number of days per year at or above 0.10, 0.50 and 1.00 inches, and the completeness flag and years of record NCEI publishes alongside each value, for the eight stations within 15 miles of a served city with at least 20 years of record (Snoqualmie Falls, Landsburg, Monroe, Tacoma #1, Seattle-Tacoma International Airport, Seattle Sand Point, Renton Municipal Airport and Everett Snohomish County Airport). Pulled through the NCEI data access service on 2026-11-10.

   Note: A normal is a 30-year statistic for one instrument at one point, not a value for the surrounding city. NCEI publishes a completeness flag with every value and this site republishes it, because a station with 20 years of record and one with 29 are not equally strong evidence. Seattle Boeing Field has 19 years behind its annual normal and is not published.

2. USDA Natural Resources Conservation Service, Soil Survey Geographic Database (SSURGO), via Soil Data Access (muaggatt.drclassdcd — drainage class, dominant condition) Open dataset Checked November 11, 2026

   The soil drainage columns for the 19 cities in the Seattle-metro climate and housing dataset: the share of each city’s mapped area whose dominant soil drainage class is somewhat poorly drained, poorly drained or very poorly drained, and the share carrying no drainage class at all. Computed on 2026-11-10 by intersecting each Census place boundary with the SSURGO map units of the King County Area, Snohomish County Area, Pierce County Area, City of Seattle, City of Tacoma and Mount Baker-Snoqualmie National Forest survey areas and area-weighting the result; the survey-area versions were read on 2026-11-11.

   Note: SSURGO assigns no drainage class to Urban land map units or to water. In Seattle, Shoreline and Burien more than four fifths of the mapped area is unrated Urban land, so their wetter-class shares are near zero because the ground is unrated, not because it drains well, and they are not compared with the other cities. Drainage class also describes natural soil in place — not the fill, the grading or the downspout run at any individual house.

3. Seattle Public Utilities (prepared by Shannon & Wilson), Seattle Landslide Study, Volume 1 Checked November 10, 2026

   That Vashon till, known locally as “hardpan”, is very dense and relatively impervious, so water soaking down through the deposits above it normally perches on top of it; that the contact between recessional outwash and till is normally less than 10 feet deep and the water perched there normally dries up in spring or summer and returns in winter; that the boundary where groundwater perches on the Lawton Clay is commonly termed “The Contact”; and that the study’s database holds 1,326 landslides reported through June 1999, records going back to 1890, about 84 percent with some human influence, landsliding in only about 1 percent of the city, and the highest densities in Southwest Magnolia, Southwest Queen Anne, Madrona, Interlaken and Alki.

   Note: The PDF prints no date; 2000 is the year Seattle Public Utilities gives for it. A 2003 update added about 110 landslides; this site quotes the original figures.

4. Seattle Department of Construction and Inspections, Tip 325, Peat Settlement-Prone Areas Explanatory summary, not the governing text Checked November 10, 2026

   That peat-rich soils settle when they are loaded by structures or fill, or when the groundwater table is lowered.

5. City of Seattle, Stormwater Code, Seattle Municipal Code Title 22, Subtitle VIII (July 2026 compilation; SMC 22.802.020 and 22.802.030) Checked November 10, 2026

   Where pumped crawl space water may go inside Seattle: SMC 22.802.020.B prohibits any discharge to a public or private drainage system that is not entirely stormwater, except as SMC 22.802.030 allows; SMC 22.802.030.B lists as permissible, unless the Director of Seattle Public Utilities finds a water quality problem, uncontaminated pumped groundwater, uncontaminated water from crawl space pumps, approved footing drains and other subsurface drains, and foundation drains; and SMC 22.802.030.C lets the Director approve drainage water to a sanitary sewer only case by case.

   Note: The city’s own compilation, which it labels unofficial; the Seattle Municipal Code is the official text. These are City of Seattle rules. Every other city in the area has its own stormwater code, which this site has not read.

6. Seattle Public Utilities, Side Sewer Permits Checked November 10, 2026

   That in Seattle a side sewer permit is required to connect a property to the public sewer or a storm drain and to repair, alter or add to a sanitary or drainage side sewer; that the whole side sewer to the public main is owned and maintained by the property owner; that for foundation drains only the solid pipe from the perforated footing drain to the drainage system counts as side sewer; that footing drains cannot be daylighted to the right of way; that piping inside the building is plumbing, permitted by Public Health; and that work in the right of way also needs a Seattle Department of Transportation permit.

7. Seattle Department of Construction and Inspections, Electrical Permit Checked November 10, 2026

   That in Seattle an electrical permit is needed whenever wiring is installed, altered, extended or connected to equipment, which covers a new receptacle or circuit for a sump pump or dehumidifier; that a professional applying needs a Washington electrical contractor’s license and a Seattle business license; and that owners may do their own electrical work on a property they own and occupy.

8. Washington State Department of Labor & Industries, City Electrical Permits & Inspections Checked November 10, 2026

   Which cities issue their own electrical permits and inspections instead of L&I. In this site’s area: Seattle, Bellevue, Kirkland, Redmond, Sammamish, Mercer Island, Lynnwood, Everett, Renton, Federal Way, Burien and Des Moines. Issaquah, Shoreline, Bothell, Kenmore, Edmonds, Kent and Auburn are not on the list, so L&I permits electrical work there.

   Note: L&I asks readers to confirm jurisdiction for a specific address with the Department of Revenue lookup the page links.

9. Washington State Legislature, RCW 19.28.041 — Electrical contractors: license required Checked November 10, 2026

   That it is unlawful to advertise, bid for or carry on the business of installing or maintaining electrical wiring or equipment without an electrical contractor license from L&I, which is separate from contractor registration.

10. Washington State Legislature, RCW 18.27.090 — Exemptions (contractor registration) (Revised Code of Washington 18.27.090(12)) Checked September 14, 2026

    That Washington’s contractor registration requirement does not apply to a person working on their own property, whether they occupy it or not, or on their personal residence, whether they own it or not — and that the exemption does not apply to someone performing the activities of a contractor on their own property for the purpose of selling, demolishing or leasing it.

    Note: The Revised Code of Washington is amended by session law and subsection numbers can move. An exemption from registration says nothing about permits.

11. U.S. Department of Energy, Building America Solution Center, Sump Pump Cover Gasket Checked September 28, 2026

    That when renovating a house with evidence of water issues, where an exterior drainage system is not feasible, drain pipe can be installed along the interior footing, draining to a sump pump — the renovation role of an interior system; that an uncovered or improperly sealed sump can let radon and other soil gases into basements and crawl spaces; and that water standing in an open or loosely lidded sump pit evaporates into the house and raises indoor relative humidity.

12. International Association of Certified Home Inspectors (InterNACHI), InterNACHI's Standard Estimated Life Expectancy Chart for Homes Explanatory summary, not the governing text Checked August 28, 2026

    The two equipment service lives the ownership-cost model turns on: a dehumidifier at 8 years and a sump pump at 7 years. This is the chart the home-inspection trade actually works from, which is why it is cited — an inspector reading a service life into a report is most often reading this one.

    Note: An industry guideline chart, not a measurement. It states its own figures are determined from research and testing under regular recommended maintenance and normal wear, and should be used as guidelines only rather than relied on as guarantees. It publishes no sample, no method and no confidence interval, and it is not specific to the Seattle area.

Sources last checked between August 28, 2026 and November 11, 2026; the date beside each one is when it was last opened. Where a figure comes from a document that is revised on a schedule, the edition or version is named above so you can confirm it against the current one yourself.