Looking for a cast iron pipe plumber in Seattle, WA? Describe your project once and up to three licensed plumbers who work in Seattle and King County get back to you with a quote. It's free and there is no obligation.
Seattle is home to about 780,995 people (2024 Census Bureau estimate), a growing community (+6.0% since 2020). With 9,298 people per sq mi, it is a densely built-up area. Homes built before the mid-1970s often still have cast iron drains reaching the end of their life.
Seattle at a glance
- Population (Census Bureau estimate, 2024)
- 780,995 (+6.0% since 2020)
- Rank in Washington
- 1st of 281 cities and towns
- Land area
- 84 sq mi
- Population density
- 9,298 people per sq mi (densely built-up)
- Type
- City (Seattle city)
- Main county
- King County
What to check before hiring in Seattle
- Camera first: a video inspection shows where and how badly the pipe is damaged.
- License and permit: in Washington, drain work is done by a licensed plumber under a permit.
- Method: ask for both lining and replacement options when possible.
- Price drivers: length, slab access, tunneling, method and restoration.
Useful official resources
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IAPMO: plumbing codes
Official information and guidance.
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NASSCO: pipeline rehabilitation
Official information and guidance.
Services available in Seattle
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Cast iron drain replacement
Replacement of cast iron drain lines with PVC, including under-slab work where needed.
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Cast iron pipe lining
Rehabilitation of cast iron drains with an epoxy or cured-in-place liner.
Frequently asked questions in Seattle
How much does cast iron replacement cost in Seattle, WA?
It depends on the length, the slab and the method. Describe your home: plumbers who serve Seattle reply with a quote.
How long does it take?
From a few days for lining to a week or more with tunneling.
Can I stay at home?
Often yes, with limited plumbing use during the work.
Which licensed plumbers will contact me?
Up to three independent licensed plumbers who serve Seattle and the surrounding area, chosen for the service you need. Your details are shared only with your consent.
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2024) and Gazetteer Files (public domain), imported on 10/31/2026. Figures describe the incorporated place or county as published; they are shown for information only.