Top Tankless Water Heater Service Companies in Seattle, Washington Ranked

A tankless water heater provides hot water on demand, eliminating the need for a bulky storage tank and offering potential energy savings. For Seattle homeowners, choosing the right on-demand water heater involves navigating local building codes, hard water conditions, and specific installation requirements for gas or electric models. This guide helps you understand the key considerations, from initial costs and sizing to essential maintenance, so you can make an informed decision and find qualified local professionals for your project.

Fast Water Heater Company

16120 Redmond - Woodinville Rd NE, Woodinville, WA 98072

Fast Water Heater Company is a water heater installation and repair provider serving Seattle, WA, and the broader West Coast including Washington, Oregon, and California. Established in 1986, the company offers services for various types of water heaters, including traditional tank and tankless models. They handle installations, repairs, and maintenance with adherence to safety and building codes, ensuring compliant and secure service. Fast Water Heater Company provides same-day installation if contacted by noon, supporting timely resolution of hot water issues.

4.9

2.1k Reviews

Ready Rooter

13222 SE 30th St Suite A-1, Bellevue, WA 98005

Ready Rooter is a plumbing and drain specialist serving Seattle, WA, and nearby areas. They offer a wide range of services including drain cleaning, sewer line repair, trenchless sewer repair, sump pump repair, tankless water heater installation, leak detection, repiping, and toilet repair. Their trenchless sewer line repair minimizes disruption while addressing sewer issues. The company is supported by experienced owners and technicians with many years in the industry. Ready Rooter provides 24/7 emergency services to assist customers whenever needed.

4.9

1.6k Reviews

Benjamin Franklin Plumbing of Redmond

18800 142nd Ave NE #2a, Woodinville, WA 98072

Benjamin Franklin Plumbing of Redmond provides plumbing services in Seattle, WA, specializing in water heater repair, tankless water heater installation, drain cleaning, and leak detection. They offer 24/7 emergency plumbing service to address urgent issues at any time. The company emphasizes routine maintenance such as annual water heater flushing and drain cleaning to help prevent common plumbing problems. They also recommend upgrades like low-flow fixtures and smart leak detectors to improve water efficiency and system reliability.

5.0

120 Reviews

George Gas Piping

601 12th Ave NW, Issaquah, WA 98027

George Gas Piping is a plumbing service based in Seattle, WA, specializing in gas piping installation for both residential and commercial projects. Their services include water heater and tankless water heater installation, furnace installation, and gas line installation and repair. They have expertise in gas repiping, appliance hookups, and supplying new gas piping from the street to homes. With over 10 years of experience, George Gas Piping serves multiple areas including Kent, Redmond, Renton, Kirkland, Issaquah, Woodinville, Sammamish, Bellevue, Bothell, and Seattle.

5.0

109 Reviews

Pelican Plumbing LLC

4181 Wheaton Wy # 3, Bremerton, WA 98310

Pelican Plumbing LLC is a plumbing contractor based in Seattle, WA, specializing in residential and commercial plumbing services. They offer whole-home re-piping, gas line installations, tankless water heater installation, sump pump repair, drain cleaning, leak detection, and water heater repair. Serving Kitsap County, Gig Harbor, and Tacoma, Pelican Plumbing focuses on high-end remodels, new construction plumbing, and safe, code-compliant gas and propane line installations. With over seven years of experience and union training, they have completed more than 100 projects, providing expert craftsmanship and reliable plumbing solutions.

5.0

109 Reviews

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Understanding Tankless Water Heater Options

When considering an on-demand hot water system, the first major decision is choosing between a gas or electric model. Each has distinct advantages and installation requirements that significantly impact your home's infrastructure and the final cost.

Gas Tankless Water Heaters are popular for their high flow rates, typically delivering between 5 to 7 gallons per minute (GPM) ¹. This makes them ideal for larger homes where multiple showers or appliances might run simultaneously. However, they require a dedicated gas line of sufficient size and specialized venting to safely exhaust combustion gases to the exterior, often using stainless steel pipes ^{2 3}. This venting work is a major component of the installation cost.

Electric Tankless Water Heaters are often easier to install in terms of venting, as they don't produce exhaust. Their primary requirement is a substantial electrical supply. Most units need a dedicated, high-amperage circuit-often between 40 to 60 amps or more-which may necessitate an upgrade to your home's electrical panel ⁴. While they can be highly efficient, their simultaneous flow rate may be lower than gas models, making proper sizing critical.

Key Installation Factors and Seattle-Specific Considerations

A successful tankless water heater installation in Seattle hinges on several technical and local factors. Ignoring these can lead to poor performance, code violations, or premature system failure.

Proper Sizing is Non-Negotiable: The unit's capacity must match your home's peak hot water demand. This involves calculating the required flow rate (GPM) and the necessary temperature rise (the difference between incoming groundwater temperature and your desired hot water temperature). An undersized unit will leave you with lukewarm water when multiple fixtures are in use ^{1 4}.

Venting for Gas Units: As mentioned, gas models require careful venting design. Direct vent systems, which pull combustion air from outside and exhaust directly outside, are common and efficient, but they must be installed according to strict manufacturer and code specifications ³. The complexity of running this venting through walls or the roof is a key labor cost driver.

Addressing Hard Water: Seattle's water is considered hard, meaning it has a high mineral content ⁵. These minerals, primarily calcium and magnesium, can rapidly accumulate inside the heat exchanger of a tankless unit, reducing efficiency, restricting flow, and eventually causing damage. Any installation plan must include a strategy for managing scale buildup ^{6 7}.

Permits and Codes: In Washington State, a permit is generally required for water heater installation or replacement ⁵. A licensed professional will handle pulling the permit, ensuring the installation meets all local building, plumbing, and electrical codes, which is crucial for safety and home insurance.

Breakdown of Costs in Seattle

The price for a tankless water heater project in Seattle varies widely based on the unit type, your home's existing infrastructure, and the scope of work. Here's a general breakdown of what to expect.

New Installation Costs: For a brand-new tankless system in a home without one, costs can range from approximately $3,500 to over $22,000^{8 2 9}. The wide range accounts for the unit itself (which can cost $1,400 to $3,900) and the necessary supporting work. If your home needs a new gas line, electrical panel upgrade, or complex venting, costs will be on the higher end ¹⁰.

Replacement Costs: If you are replacing an existing tankless water heater with a new one, the process is often more straightforward. In these cases, costs in Seattle typically fall between $7,000 and $9,000, as some existing infrastructure (like venting or wiring) may be reusable ^{8 2}.

Additional and Hidden Costs: Always budget for ancillary work. Upgrading a gas line can cost $1,000 or more. Installing the required stainless steel venting is another significant expense. For electric models, upgrading a service panel to add a dedicated circuit can cost several thousand dollars. These factors make a detailed, in-home estimate essential ^{8 2}.

Essential Maintenance and Common Repairs

To protect your investment and ensure a long service life, proactive maintenance is critical, especially in Seattle's hard water environment.

Annual Descaling: The most important maintenance task for any tankless water heater in Seattle is an annual descaling (or flushing) ^{5 7}. This process circulates a vinegar or commercial descaling solution through the heat exchanger to dissolve mineral deposits. Neglecting this can lead to reduced efficiency, error codes, and costly repairs. Many local plumbers offer maintenance plans that include this service.

Recognizing Signs of Trouble: Be aware of symptoms that indicate your on-demand heater needs service:

• Fluctuating water temperature, especially during simultaneous use.
• Reduced hot water flow or pressure.
• No hot water at all.
• Error codes displayed on the unit's control panel.
• Unusual noises like kettling or rumbling from the unit ^{6 7}.

Repair Costs: Basic repairs, such as replacing a flow sensor or cleaning a filter, might cost between $150 and $400¹¹. More significant repairs, like replacing a compromised heat exchanger due to scale damage, can run into the thousands of dollars, underscoring the value of regular maintenance ^{12 13}.

Choosing the Right Professional for the Job

Given the technical complexity, selecting an experienced installer is as important as choosing the right unit. Look for a licensed plumbing professional who demonstrates specific expertise with tankless systems.

Key Qualifications to Seek:

• Licensing and Insurance: Verify they hold a current Washington State plumbing license and carry adequate liability insurance.
• Local Code Knowledge: They should be familiar with Seattle and King County permit processes and code requirements.
• Hard Water Experience: Ask about their specific protocol for installing and maintaining systems in hard water areas. Do they recommend or install inline scale inhibition systems?
• Sizing Process: A reputable pro will perform a detailed load calculation based on your home's fixtures and usage patterns, not just a rule-of-thumb guess.
• Warranty Support: Ensure they are authorized dealers or installers for the brand they recommend, which helps with warranty validation.

By focusing on these criteria, you can find a specialist capable of designing a system that delivers reliable, efficient hot water for years to come.

Frequently asked questions

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