Published:
January 3, 2018
Last updated:
April 1, 2026
Rules for Mortgage Interest Deduction in Washington State
In This Article

For many home buyers in Washington, the ability to deduct mortgage interest has historically been a key financial benefit of homeownership. However, tax law changes over the past several years have significantly altered how—and whether—homeowners benefit from these deductions.

The current rules stem from the Tax Cuts and Jobs Act, which introduced new limits and guidelines that remain in effect today. Understanding these rules is especially important for buyers in higher-cost markets like Seattle.

Note: Many of the individual tax provisions established by the Tax Cuts and Jobs Act are slated to sunset after 2025. If no legislative changes are made, tax brackets are expected to increase to pre-2018 levels, the standard deduction will shrink, and the rules governing itemized deductions will likely be revised.

Key Changes Under the Tax Cuts and Jobs Act

The Tax Cuts and Jobs Act (TCJA) made several important changes that affect homeowners in Washington State:

  • Mortgage interest deduction capped at $750,000 for loans originated after December 15, 2017
  • State and local tax (SALT) deductions capped at $10,000
  • Standard deduction nearly doubled, reducing the number of taxpayers who itemize

For homeowners with mortgages taken out before the cutoff date, the previous $1 million mortgage interest deduction limit may still apply due to grandfathering provisions.

Do Washington Homeowners Still Benefit From the Deduction?

One of the most important—and often overlooked—impacts of the TCJA is the increase in the standard deduction.

As a result, many homeowners no longer itemize their deductions. Instead, they take the standard deduction, which means they may not directly benefit from the mortgage interest deduction at all.

Whether you benefit depends on your total itemized deductions, which may include:

  • Mortgage interest
  • Property taxes
  • Charitable contributions
  • Other eligible expenses

If these combined deductions do not exceed the standard deduction, itemizing may not provide additional tax savings.

Mortgage Rates for WA State

Special Considerations for Seattle Homebuyers

In higher-cost housing markets like Seattle, home prices often exceed national averages.

This creates two important considerations:

  1. Loan amounts may exceed the $750,000 deduction limit, reducing the portion of interest that is tax-deductible
  2. Buyers are more likely to reach the SALT deduction cap, limiting property tax deductions

At the same time, Seattle’s housing market has shifted in recent years, with more moderate price growth and increased inventory compared to peak conditions. While affordability remains a challenge, buyers today may have more flexibility when entering the market.

Rules for Deducting Home Equity Loan Interest

The TCJA also changed how interest on home equity loans and lines of credit (HELOCs) is treated:

  • Interest is only deductible if the funds are used to buy, build, or substantially improve the home
  • Using home equity funds for other purposes (such as debt consolidation or personal expenses) does not qualify for a deduction

Unlike mortgage interest rules, this provision applies regardless of when the loan was originated.

Provisions Set to Expire

One of the most important considerations for today’s buyers is that many TCJA provisions are scheduled to expire after 2025 unless extended by Congress.

Potential changes could include:

  • The mortgage interest deduction limit reverting to $1 million
  • Adjustments or removal of the $10,000 SALT cap
  • Changes to the standard deduction

Because of this uncertainty, homebuyers should stay informed and consider how future tax law changes could impact long-term affordability.

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Have Questions or Need a Home Loan in WA State?

Looking to take out a mortgage in Washington? We can help. Sammamish Mortgage is a local, family-owned company based in Bellevue, WA. We serve borrowers across WA, OR, CO, CA, and ID since 1992. We provide a variety of mortgage programs with flexible criteria, and we’d love the opportunity to help you apply for a home loan. Visit our website to get an instant rate quote or to use our online mortgage calculator. Please contact us if you have mortgage-related questions or to get pre-approved for a mortgage.