What does crawl space drainage cost in Seattle?

This site models interior perimeter drainage with a sump basin and pump at $4,025 to $7,175 in 2026 Seattle-metro pricing for a 1,200 to 1,500 sq ft crawl space, before sales tax. Curtain drains for hillside lots add $2,250 to $5,375. Exterior downspout work and regrading is $700 to $2,250. Complex hillside systems with multiple interceptors and long discharge runs can reach $7,625 to $14,325. These are modeled estimates rather than collected quotes; a free in-home inspection gives the actual quote for your site.

What is the difference between a French drain and a perimeter drain?

Both use perforated pipe in gravel-lined trenches; the difference is location and purpose. A perimeter drain runs along the inside or outside of the foundation footing and collects water that has already reached the foundation. A French drain typically runs through the yard or under a problem area and collects surface or shallow sub-surface water before it reaches the foundation. Hillside projects often use both: a French or curtain drain uphill from the house plus an interior perimeter drain as a backup.

Do I need a permit for drainage work in Seattle?

Usually for some part of it. Inside the City of Seattle, connecting a drain or a sump discharge to the public drainage system, or altering a drainage side sewer, takes a side sewer permit from Seattle Public Utilities, and a new circuit for the pump takes an electrical permit. The city's stormwater code lists uncontaminated water from crawl space pumps and foundation drains among the discharges allowed into the drainage system, but drainage water may go to a sanitary sewer only with SPU's approval, and the city's side sewer rule says water from subsurface drains passes through a catch basin before it reaches a public system and may never discharge onto a public sidewalk. Whether SDCI wants a building permit for the interior drain itself was not found in any city document this site has read, so ask the permit desk. Every other city has its own rules. Permits belong in the written scope, pulled by whoever does the work; ask for a copy.

Can drainage work be done in winter?

Yes. Drainage is year-round work, and winter has one real advantage: it is the season when you can see exactly where water is entering. Interior trenching is unaffected by weather. Exterior work like regrading or trench installation outside the house can slow during sustained heavy rain, but minor wet weather is normal. If the crawl space is actively flooding, say so when you request the inspection.

Will a sump pump alone solve my problem?

Only if the water already reaches a sump basin on its own. In most crawl spaces with a water problem, water enters at the foundation walls and pools across the soil; without a perimeter drain to collect that water and route it to a basin, a standalone sump pump just sits there. A perimeter drain plus sump is the typical scope. Standalone sump installs make sense only when an existing drain already feeds a basin and the pump itself has failed.

Do I need an interior perimeter drain or exterior work?

Interior perimeter drains are the common answer for crawl spaces, because they are installed from inside the crawl space with no excavation, no landscape damage, and no disruption to driveways or mature plantings. Exterior work — regrading, extending downspouts, cutting a curtain drain uphill of the house — is worth doing first when the water is clearly arriving from a surface source, since it is often much cheaper than anything done under the house. The honest sequence is to fix the obvious surface causes, then see what is left. A contractor who quotes an interior system without first asking where your downspouts discharge has skipped a step. Exterior foundation waterproofing with a full membrane is a different and much larger scope, and it usually only makes financial sense when the foundation is being excavated anyway.

What is a curtain drain and do I need one?

A curtain drain is a perimeter drain installed uphill from the foundation, designed to intercept groundwater flowing downhill before it reaches the house. It is typically 2 to 4 feet deep with gravel, perforated pipe wrapped in filter fabric, and a discharge at one end. If your lot slopes toward the house and you have ongoing crawl space water, a curtain drain is often the most effective single intervention. Two Seattle cautions: the trench is excavation, so the utility locate notice applies, and on a steep or seeping slope the parcel may sit in a landslide-prone area under the city's critical areas code, which is worth checking on SDCI's map before anyone digs.

How long does drainage work take?

Two to four days for an interior perimeter drain with sump. Downspout and grading work: usually one.

Crawl Space Drainage in Seattle, WA

Interior perimeter drains, curtain drains, sump basins, and exterior grading for crawl spaces across the Seattle metro. Start with a free in-home inspection and a written, no-obligation quote.

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Standing water and saturated soil in a crawl space, the condition an interior perimeter drain is built to solve

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Overview

What Is Crawl Space Drainage?

Last updated November 11, 2026

Water under a house always has a story: it ran off the yard during a downpour, it pushed through a foundation crack under pressure, or it rose up from saturated ground and just sat there. Drainage is the part of the job that answers the question of where that water goes instead. Trenches, pipe, gravel, a basin, a pump, and the grading outside that should have sent it elsewhere in the first place. Get the drainage right and most of the other crawl space problems get a lot easier to solve.

The usual scope for a crawl space that takes on water is an interior perimeter drain: a trench cut along the inside face of the foundation walls, lined with washed gravel, fitted with a perforated drain pipe wrapped in filter fabric, sloped to a sump basin at the low point, and pumped out to an approved discharge point. Variations include French drains (mid-yard or interior runs to capture surface or sub-surface flow), curtain drains (uphill trenches that intercept groundwater before it reaches the foundation), and footing drains (deeper exterior installs at the foundation footing). Less invasive measures, downspout extensions and regrading, often go in at the same time.

Drainage work is distinct from waterproofing in scope but they overlap in practice. Drainage is the plumbing side: where the water flows. Waterproofing is the moisture-control side: barriers, sealants, and conditioning. Most projects bundle both, because installing a perimeter drain without also addressing vapor and humidity leaves the air problem unsolved.

A sump pump without a perimeter drain is a bucket in the wrong corner. Collect the water first; then the pump has something to do. Why drains come before pumps in every honest scope

Signs to Watch For

Signs You May Need Crawl Space Drainage

Standing water on the crawl space soil after a rain event
Sump pump that runs every few minutes during winter rain
Visible seepage or wet streaks on the inside of foundation walls
Mud or saturated soil under the house even between storms
Downspouts that dump water within a few feet of the foundation
Yard that holds water in low spots near the house
High-water-mark lines on foundation walls indicating past flooding
Hillside lot with uphill drainage that flows toward the house

Seattle Context

Why Crawl Space Drainage Matters in Seattle

The Seattle area's water arrives in one season and sits on one kind of ground. At Seattle-Tacoma International Airport the 1991–2020 normal is 39.34 inches of precipitation a year, and 75.4% of it falls from October through March. Where the ground is Vashon till, which the Seattle Landslide Study describes as very dense and relatively impervious (locally, “hardpan”), water soaking down through the looser soil above perches on top of it instead of draining away. The same study puts the contact between that looser outwash and the till normally less than 10 feet down, and says the water perched there usually dries up in spring or summer and returns in winter. That is the pattern a wet crawl space follows: dry in August, wet from November.

The soil survey shows how uneven this is, and where it goes blank. Among the cities this site covers whose soil the survey rates, the largest shares of mapped area in the wetter drainage classes are in Auburn, Issaquah, Kent and Bothell. Seattle itself is the opposite case: 87.1% of its mapped area carries no drainage rating at all, because the survey does not rate urban land. For most Seattle lots the map is silent, and the crawl space after a wet week in January is the better evidence.

Three drainage situations come up again and again:

Sloped lots. Where the ground rises behind the house, groundwater moving downhill meets the foundation. A curtain drain cut uphill intercepts it. In Seattle, check the parcel on SDCI's environmentally critical areas map before any trenching on a slope: landslide-prone areas include slopes of 40 percent or more and areas with springs or groundwater seepage, and most of the map's layers are advisory, so a property can carry a critical area the map does not show.
Flat lots where water collects at the foundation. An interior perimeter drain with a sump is the workhorse scope here, because it collects water at the footing from inside the crawl space without digging up the yard.
Surface fixes first. Seattle Public Utilities asks homeowners to send downspout water at least 5 feet from the foundation (10 is better), not onto a neighbor's lot or over a steep slope, and the city's stormwater manual sets the same 5-foot minimum for a splashblock. Extending downspouts and regrading away from the house handles a surprising amount of crawl space water without trenching inside.

Two code and site points are worth knowing. The residential code's only drainage rule for the space under a house is a grade rule: where groundwater can rise to within 6 inches of the finished floor at the perimeter, or surface water does not drain readily, the under-floor grade has to be as high as the outside grade unless an approved drainage system is provided. And in Seattle's peat settlement-prone areas, SDCI warns that peat-rich soils settle when the groundwater table is lowered, which is what a drain and pump do; on a parcel mapped that way, ask the contractor and SDCI how the drain will be designed before it is dug.

Process

How Crawl Space Drainage Works, Step by Step

Site inspection and drainage diagnosis

Gutters, downspouts, grading, and crawl space conditions are checked to find the actual water sources. Low-cost exterior fixes come first if those alone will solve it.
Scope and routing plan

The drain run, sump location, and discharge route are laid out, and you receive a written scope: linear feet of pipe, basin size, pump specs, discharge plumbing, and which permits it needs.
Trench and install

Trenches are cut at the inside face of the foundation, lined with washed gravel, fitted with perforated pipe in filter sock, and sloped to the sump basin.
Test and final walk-through

A pump test confirms basin fill and discharge flow, any required permit inspection is closed out, and you get a walk-through of how the system operates and what maintenance it needs.

Pricing Factors

What Affects the Cost of Crawl Space Drainage?

Modeled 2026 Seattle-area range, before sales tax: Interior perimeter drainage systems typically run $4,025 to $7,175 in the Seattle metro, including drain pipe, sump basin, pump, and discharge plumbing. Curtain drains add $2,250 to $5,375 depending on length and excavation depth. Exterior downspout work and regrading is usually $700 to $2,250. Complex hillside drainage projects with multiple interceptors can reach $7,625 to $14,325.

Linear feet of drain pipe : A perimeter drain runs the length of the foundation walls it protects, so the house footprint and how much of the perimeter takes on water set most of the material and labor.
Drain type : Interior perimeter drain, French drain, curtain drain, and footing drain each have different labor and materials.
Discharge route : A short run to an approved discharge point is cheapest; a connection to the public drainage system, or a long buried run, adds labor and, in Seattle, a side sewer permit.
Sump basin and pump : The basin and pump are included in the drainage range. A battery backup is the common upgrade: on a standalone sump installation it brings the modeled total to $2,250 to $4,025, against $1,600 to $3,125 without one.
Exterior work : Downspout extensions and regrading often go in alongside interior drains. Any digging outside needs a utility locate requested two to ten full business days ahead, unless it is an owner digging less than 12 inches deep on their own home’s lot.
Soil type : Dense glacial till, the “hardpan” of local usage, digs slower than sand or loose fill; rocky ground adds chiseling time.
Permits : In Seattle, connecting a drain to the public drainage system takes a side sewer permit from Seattle Public Utilities, and a new circuit for the pump takes an electrical permit. Other cities set their own rules; the written scope should say which permits are included.
Access : Tight side yards, locked gates, and low crawl space clearance all slow the work.
Season and water table : Trenching through saturated January soil is slower than dry-season work, and winter is also when the water shows where it is coming in.
Obstacles in the trench line : Piers, ductwork, plumbing runs, and old concrete footings in the trench path each add hand-digging time.

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Common Issues

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Service Area

Crawl Space Drainage by City

Each city page describes the local ground and housing stock, which shape what a crawl space drainage scope involves there. These are 4 of the 19 service areas this site covers.

More Crawl Space Repair

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Areas We Cover

King County

Snohomish County

All 19 service areas

Sources

The rain normal and soil drainage figures are this site's published climate and housing dataset values; the till and perched-water description is the Seattle Landslide Study's; the grade rule is from the 2021 Seattle Residential Code; the discharge, side sewer, downspout, electrical, critical-areas and peat rules are the City of Seattle's; the locate notice is Washington law. Installed ranges are this site's modeled estimates; see the cost methodology.

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.
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.
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.
Seattle Department of Construction and Inspections, 2021 Seattle Residential Code, Chapter 4, Foundations (Section R408, pages 4-47 and 4-48) Checked November 10, 2026

Two things. First, that Seattle’s R408.1, R408.2 and R408.3 carry the Washington-amendment marker and read the same as WAC 51-51-0408, apart from “Appendix F” where the state rule says “Appendix AF”; the copy shows the model code’s wording struck through, including its menu of alternatives for an unvented crawl space (dehumidification, conditioned supply air, perimeter-wall insulation), which is how the two numbered conditions of R408.3 are read as applying together. Second, the sections Washington does not amend, R408.4 to R408.6: an access opening not smaller than 18 by 24 inches through the floor or 16 by 24 inches through a perimeter wall; the under-floor grade cleared of vegetation and organic material, and forms and construction materials removed; and the under-floor grade as high as the outside finished grade where groundwater can rise to within 6 inches of the finished floor at the perimeter or surface water does not drain readily, unless an approved drainage system is provided.

Note: The PDF marks additions by underline, which is lost when its text is extracted. “No Seattle-only change to R408” is drawn from the match with the state rule, not from a statement by the city. R408.4 to R408.6 are model code text and are summarised here, not reproduced.
Seattle Department of Construction and Inspections, 2021 Seattle Residential Code, Chapter 1, Administration (Sections R105.1 and R105.2) Checked November 10, 2026

When a building permit is needed in the City of Seattle. R105.1: a permit is required to construct, alter or repair a building, and all work must meet the code whether or not a permit is required. R105.2 item 1: no permit for minor repairs or alterations valued at $6,000 or less in any six-month period, provided no loadbearing support is removed, reduced, altered or relocated and ventilation is not reduced. R105.2 item 2: no permit, provided the building envelope is not changed, for listed work that includes insulating existing buildings and in-kind or similar replacement or repair of deteriorated members.

Note: City of Seattle only, and it is the building permit only: electrical, plumbing and side sewer permits are separate. The chapter does not say how the department classifies a ground cover, a sealed crawl space or a sump basin.
Seattle Public Utilities, Drainage System Explanatory summary, not the governing text Checked November 10, 2026

SPU’s homeowner advice to direct downspout flows at least 5 feet from the foundation (10 feet is better), not onto a neighbor’s property or over a steep hill, and to coordinate approved discharge points with SDCI.
Seattle Department of Construction and Inspections and Seattle Public Utilities, Seattle Stormwater Manual, Volume 3, Project Stormwater Control (2026 edition, Directors’ Rule 03-2026 / DWW-200, effective July 1, 2026; sections 5.3.1.2 and 5.3.3.5) Checked November 10, 2026

That a downspout splashblock or rock pad must be at least 5 feet from a structure, with a 10-foot setback recommended from a building with a basement, and serve no more than 700 square feet of roof (5.3.3.5); and that dispersing roof water is not typically permitted in landslide-prone areas or within a steep-slope setback of ten times the slope’s height (5.3.1.2).

Note: City of Seattle rules. Other cities in the area use their own stormwater manuals.
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.
City of Seattle, Department of Planning and Development and Seattle Public Utilities, Requirements for Design and Construction of Side Sewers (Drainage and Wastewater Discharges) (DPD Director’s Rule 4-2011 / SPU Director’s Rule 2011-004, effective April 8, 2011; pages 26 and 27) Checked November 10, 2026

Seattle’s rules for subsurface drains, which the rule defines to include drains along the interior or exterior footings of a building: drainage may not go to a sanitary sewer unless specifically allowed; water collected by subsurface drains must pass through a catch basin before it is discharged to a public system or watercourse; subsurface drains may not discharge onto a public sidewalk or public place; and downspouts may never be connected directly to a groundwater collection system.

Note: Fifteen years old, and it names the Department of Planning and Development, since renamed; side sewer permits now come from Seattle Public Utilities. It is still the document SDCI links for side sewer requirements, but confirm any single provision with SPU before relying on it. City of Seattle only.
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.
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.
Seattle Department of Construction and Inspections, Environmentally Critical Areas (ECA) Code Explanatory summary, not the governing text Checked November 10, 2026

That Seattle’s environmentally critical areas (SMC chapter 25.09) include landslide-prone, liquefaction-prone and peat settlement-prone areas; that a parcel is looked up on SDCI’s GIS map with the ECA layer switched on; that most of those map layers are advisory; and that a property can contain a critical area the map does not show.
City of Seattle, Seattle Municipal Code 25.09.012, Designation and definitions of environmentally critical areas (Municode, version of September 25, 2026) Checked November 10, 2026

How Seattle defines three kinds of geologic hazard area. Landslide-prone areas: known landslide areas plus potential ones, including areas with springs or groundwater seepage and slopes of 40 percent or more over at least 10 feet of rise. Peat settlement-prone areas: Category I and II areas on the code’s maps, drawn from the city’s identified bogs plus a 50-foot or 25-foot buffer. Liquefaction-prone areas: areas typically underlain by low-density cohesionless soils, usually with a shallow water table, that lose substantial strength in an earthquake.
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.
Washington State Legislature, RCW 19.122.030, Excavators and facility operators — Duties before excavation Checked November 10, 2026

That before excavating, an excavator marks the area and notifies facility operators through a one-number locator service not less than two full business days and not more than ten full business days before the work begins.
Washington State Legislature, RCW 19.122.031, Exempted activities Checked November 10, 2026

That the locate notice is not required for an excavation less than twelve inches deep on private non-commercial property done by the owner or occupier, or their employee, so a trench dug to a foundation footing is not exempt.

Sources last checked between November 10, 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.

Questions, Answered

Crawl Space Drainage FAQs

: This site models interior perimeter drainage with a sump basin and pump at $4,025 to $7,175 in 2026 Seattle-metro pricing for a 1,200 to 1,500 sq ft crawl space, before sales tax. Curtain drains for hillside lots add $2,250 to $5,375. Exterior downspout work and regrading is $700 to $2,250. Complex hillside systems with multiple interceptors and long discharge runs can reach $7,625 to $14,325. These are modeled estimates rather than collected quotes; a free in-home inspection gives the actual quote for your site.
: Both use perforated pipe in gravel-lined trenches; the difference is location and purpose. A perimeter drain runs along the inside or outside of the foundation footing and collects water that has already reached the foundation. A French drain typically runs through the yard or under a problem area and collects surface or shallow sub-surface water before it reaches the foundation. Hillside projects often use both: a French or curtain drain uphill from the house plus an interior perimeter drain as a backup.
: Usually for some part of it. Inside the City of Seattle, connecting a drain or a sump discharge to the public drainage system, or altering a drainage side sewer, takes a side sewer permit from Seattle Public Utilities, and a new circuit for the pump takes an electrical permit. The city's stormwater code lists uncontaminated water from crawl space pumps and foundation drains among the discharges allowed into the drainage system, but drainage water may go to a sanitary sewer only with SPU's approval, and the city's side sewer rule says water from subsurface drains passes through a catch basin before it reaches a public system and may never discharge onto a public sidewalk. Whether SDCI wants a building permit for the interior drain itself was not found in any city document this site has read, so ask the permit desk. Every other city has its own rules. Permits belong in the written scope, pulled by whoever does the work; ask for a copy.
: Yes. Drainage is year-round work, and winter has one real advantage: it is the season when you can see exactly where water is entering. Interior trenching is unaffected by weather. Exterior work like regrading or trench installation outside the house can slow during sustained heavy rain, but minor wet weather is normal. If the crawl space is actively flooding, say so when you request the inspection.
: Only if the water already reaches a sump basin on its own. In most crawl spaces with a water problem, water enters at the foundation walls and pools across the soil; without a perimeter drain to collect that water and route it to a basin, a standalone sump pump just sits there. A perimeter drain plus sump is the typical scope. Standalone sump installs make sense only when an existing drain already feeds a basin and the pump itself has failed.
: Interior perimeter drains are the common answer for crawl spaces, because they are installed from inside the crawl space with no excavation, no landscape damage, and no disruption to driveways or mature plantings. Exterior work — regrading, extending downspouts, cutting a curtain drain uphill of the house — is worth doing first when the water is clearly arriving from a surface source, since it is often much cheaper than anything done under the house. The honest sequence is to fix the obvious surface causes, then see what is left. A contractor who quotes an interior system without first asking where your downspouts discharge has skipped a step. Exterior foundation waterproofing with a full membrane is a different and much larger scope, and it usually only makes financial sense when the foundation is being excavated anyway.
: A curtain drain is a perimeter drain installed uphill from the foundation, designed to intercept groundwater flowing downhill before it reaches the house. It is typically 2 to 4 feet deep with gravel, perforated pipe wrapped in filter fabric, and a discharge at one end. If your lot slopes toward the house and you have ongoing crawl space water, a curtain drain is often the most effective single intervention. Two Seattle cautions: the trench is excavation, so the utility locate notice applies, and on a steep or seeping slope the parcel may sit in a landslide-prone area under the city's critical areas code, which is worth checking on SDCI's map before anyone digs.
: Two to four days for an interior perimeter drain with sump. Downspout and grading work: usually one.

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