Basement Waterproofing Cost in Portland, OR [2025 Data]

Normal Range: $2,094 - $6,720

Basement waterproofing in Portland, OR costs $4,407, on average, and most homeowners pay somewhere between $2,094 and $6,720 for a complete waterproofing system.

How we get this data
modern finished basement
Photo: Nate / Adobe Stock Photography
modern finished basement
Photo: Nate / Adobe Stock Photography
Highlights
  • Portland's persistent rain creates concerns for wetness and dampness in Portland basements.

  • While local homes aren't usually at risk for flooding, letting basements remain damp and moist can lead to long-term mold issues.

  • While costs for basement waterproofing in Portland are above average, homeowners do get relief from the fact that Portland is one of the only states without sales tax. In most other states, the materials needed for basement waterproofing are subject to state and city taxes.

Homeowners looking for ways to keep their basements dry against Portland's persistent rainfall can explore basement waterproofing. On average, the cost for basement waterproofing in Portland is $4,407. However, homeowners are paying between $2,094 and $6,720 for different waterproofing options. Your contractor will use details such as basement size, your preference for interior versus exterior waterproofing, and other factors to compile a quote for Portland basement waterproofing for you.

Basement Waterproofing Cost Factors 

Your contractor will conduct an inspection of your home's basement and foundation to help you create a plan for waterproofing. Things like weak spots for water intrusion, visible signs of basement water damage, and your home's orientation will all be factored into a plan for keeping water out. 

8 signs basement waterproofing is needed illustrated, including mold, leaks, and musty smells

Basement Size

The cost to waterproof a basement falls between $3 and $10 per square foot on average, although where in this range your pricing falls depends largely on the type of waterproofing method you choose. In any case, large spaces require more time, labor, and material to waterproof than small spaces. Therefore, the larger your basement, the more you can expect to pay for waterproofing for any given method.

Below is a breakdown of how much you might spend for a range of basement sizes.

Basement Size (Sq. Ft.) Average Cost Range
300$1,200–$3,300
500$2,000–$5,500
700$2,800–$7,700
900$3,600–$9,900
1,000$4,000–$11,000
1,200$4,800–$13,200
1,500$6,000–$16,500
1,700$6,800–$18,700
2,000$8,000–$22,000

Interior vs. Exterior Waterproofing

Depending on where your basement water issues are stemming from and what solutions your expert recommends, you may need either interior or exterior waterproofing services. Some homes require both. Interior basement waterproofing is often more affordable because it doesn’t involve excavation and backfilling. Something like installing damp-proofing around the exterior of your foundation would require a lot of digging, which drastically increases labor costs.

You’ll spend an average of $3,000 on interior waterproofing services, while extensive exterior services will cost an average of $7,000.

Waterproofing Method

As mentioned above, professionals can waterproof your basement from the exterior or the interior. Exterior methods are more effective because they’re preventative, but they’re also more expensive because they tend to require excavation, which is time-consuming. The table below includes a list of basement waterproofing methods along with cost ranges for each.

Waterproofing MethodInterior or ExteriorAverage Cost Range
Dehumidifiers Interior$500–$1,200 each
Vapor barriers Interior$1,250–$2,200
Weeping tiles / interior French drainExterior / Interior$65–$110 per square foot
Baseboard channels Interior$25–$40 per linear foot
Yard grading Exterior$300–$2,600
Underground downspoutExterior$225–$1,900
Gutter systemExterior$4–$50 per linear foot
Liquid membraneExterior$3–$5 per square foot

Basement Waterproofing Pro Costs

Basement waterproofing companies in Portland set prices for waterproofing based on the amount of materials and work hours needed to complete the project. Generally, labor accounts for 40% to 60% of total waterproofing costs. Contractors build costs for things like licensing and insurance into their rates.

Permits

In general, any type of basement waterproofing or finishing project in Portland requires a permit. While minor waterproofing efforts that include adding waterproofing paints or membranes may not require permits, you'll need a permit if your project involves structural changes, earthmoving equipment on the exterior of your foundation, yard grading, plumbing, or electric work. Expect to pay a minimum of $153 to $202 for a basic renovation permit in Portland.

Local Labor

On average, basement waterproofing professionals in Portland charge between $180 and $220 hourly. Rates are generally higher when multiple workers are needed for a basement project because contractors need to account for things like wages and workers' compensation insurance.

Taxes

Homeowners don't have to worry about paying state or local sales tax for the materials purchased for this project because Oregon does not have sales tax.

Insurance

It is necessary to hold both general liability insurance and a surety bond in order to remain licensed as a contractor in Oregon. Contractors with employees must also cover costs for workers' compensation insurance. Insurance costs can total $119 to $390 for the average contractor.

Licensing and Certification

Contractors in Portland, Oregon must be licensed by the Oregon Construction Contractors Board (CCB) before doing any work valued above $1,000. In addition to undergoing pre-licensing education, contractors must pay a two-year licensing fee costing $400.

Does Basement Waterproofing Increase Home Value?

Yes, basement waterproofing is considered a sound investment for Portland homeowners. While Portland isn't prone to severe flooding, general dampness and moisture presence are common concerns for homeowners. By waterproofing a basement, a homeowner can reduce risks for mold and mildew that can dramatically decrease home value or require expensive renovations.

How Angi Gets Its Cost Data

Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We survey real Angi customers about their project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects. 

Want to help us improve our cost data? Send us a recent project quote to [email protected]. Quotes and personal information will not be shared publicly.

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