Commercial Water
Heater Systems
Commercial hot water demands are different — higher volume, continuous draw, and systems that can't afford downtime. We design, install, and service commercial water heater systems sized and configured for the job.
Serving SW Washington & Portland, OR · Multi-family, restaurant, commercial & light industrial
What We Do
Commercial Water Heater
Services
New System Installation
From load calculation and equipment selection to permitting, installation, and inspection — we manage commercial water heater projects start to finish.
- Hot water demand load calculation
- Equipment sizing and selection
- Permit application and coordination
- Gas line sizing and extension
- Commercial venting installation
- Recirculation system design and installation
- Final inspection and commissioning
Manifolded & Linked Systems
When a single unit can't meet demand — or when redundancy is required — we design and install multi-unit manifolded systems that stage intelligently and keep hot water available even if one unit goes offline.
- Multi-unit manifold design
- Demand-staged system configuration
- Balanced supply and return headers
- Individual unit isolation valves
- Expansion tank sizing for the full system
- Mixing valve installation for scald protection
- System controls and aquastat setup
Replacement & Upgrades
Like-for-like replacements handled efficiently to minimize downtime, plus system upgrades that improve efficiency, capacity, or redundancy for changing building needs.
- Emergency replacement with minimal downtime
- Tank to tankless conversion
- Capacity upgrades for growing demand
- Efficiency upgrades (ENERGY STAR commercial units)
- Single unit to manifolded system conversion
- Recirculation pump replacement and upgrade
- Code compliance updates on existing systems
Not Just a Bigger Residential Unit
Commercial Systems Require
a Different Approach
A commercial water heater installation isn't simply a larger version of a residential job. The demands are different, the equipment is different, the code requirements are different, and the consequences of an undersized or improperly installed system are felt immediately — in cold showers, failed health inspections, or a flooded mechanical room.
We size systems based on actual demand calculations, not rule-of-thumb estimates. We design piping layouts that deliver consistent pressure and temperature to every point of use. And we install venting and combustion air systems that meet the specific requirements of commercial-grade equipment — because a commercial burner puts out significantly more heat than any residential unit, and the vent system has to handle it.
Load Calculation First
We calculate peak demand based on fixture count, usage patterns, and recovery requirements — not estimates. A restaurant at lunch service and an apartment building at 7am have very different hot water profiles.
Permits Are Required
Commercial water heater installations require permits and inspections in Washington and Oregon. We handle the permitting process and schedule inspections — it's not something to skip or work around.
Downtime Has Real Costs
A restaurant without hot water can't pass a health inspection. An apartment building without hot water has legal obligations to tenants. We plan installations to minimize downtime and have contingency approaches for critical replacements.
Redundancy Is Worth Planning For
A manifolded multi-unit system costs more upfront than a single large unit. It also means that when one unit fails — and eventually they all do — the building still has hot water while the repair happens.
Who We Work With
Buildings and Businesses
We Serve
Apartment & Condo Buildings
Multi-unit residential buildings are among the most demanding hot water applications — high simultaneous draw, tenant expectations, and legal obligations around continuous supply. We design systems that meet peak demand without oversizing, and we plan for recovery time when multiple units draw at once.
Restaurants & Commercial Kitchens
High-temperature dishwasher requirements, hand-sink code compliance, and the reality that a health inspection doesn't wait — restaurant hot water systems require careful sizing and reliable equipment. We understand what commercial kitchen demands look like at peak service.
Gyms, Hotels & Lodging
Post-workout shower rushes, hotel check-in peaks, and continuous turnover create usage patterns that can overwhelm an undersized system. Manifolded tankless or staged tank systems are often the right answer — delivering consistent supply without the standby loss of a single large tank.
Offices, Retail & Light Industrial
Smaller commercial buildings often have simpler hot water needs, but still require properly permitted, correctly vented commercial equipment — not residential units pressed into service beyond their rating. We right-size these systems and install them to code.
Common Questions
Commercial Water Heater FAQs
Questions we hear from building owners, property managers, and business operators — answered plainly.
Call 360-209-4048 →How do I know if I need a manifolded system or a single large unit? +
What venting is required for commercial gas water heaters? +
Do commercial water heater installations require a permit? +
What is a mixing valve and why does a commercial system need one? +
How is commercial hot water load actually calculated? +
What areas do you serve for commercial work? +
What Customers Say
Trusted by Neighbors Across
SW Washington & Portland
"Aaron was on time and thorough with his explanation of what work would need to be done. He answered all of my questions and went above and beyond by indicating other parts of my plumbing that would benefit from an upgrade. He is honest and thoughtful."
"HONEST, Professional, clean, did great work, super fair price. What more could you ask for?"
"Excellent service, timing, and very knowledgeable. Will be using Maxwell Plumbing again in the future and referring others to them."
"Maxwell Plumbing did a fantastic job hooking up our outdoor kitchen. He went above and beyond making us understand what he was doing and why. Communicated throughout the entire project and was reasonable on price."
"Excellent experience including scheduling, communication to service provided. Highly recommend."
"Always professional, kind, and helpful. Our go-to plumber."
Let's Talk
Tell Us About
Your Building.
Whether you're planning a new installation, replacing aging equipment, or dealing with a system that can't keep up with demand — we'll assess your situation and put together an honest recommendation. Commercial estimates are free.
Common Questions
Commercial Water Heater FAQs
Questions we hear from building owners, property managers, and business operators — answered plainly.
Call 360-209-4048 →How do I know if I need a manifolded system or a single large unit? +
What venting is required for commercial gas water heaters? +
Do commercial water heater installations require a permit? +
What is a mixing valve and why does a commercial system need one? +
How is commercial hot water load actually calculated? +
What areas do you serve for commercial work? +
What Customers Say
Trusted by Neighbors Across
SW Washington & Portland
"Aaron was on time and thorough with his explanation of what work would need to be done. He answered all of my questions and went above and beyond by indicating other parts of my plumbing that would benefit from an upgrade. He is honest and thoughtful."
"HONEST, Professional, clean, did great work, super fair price. What more could you ask for?"
"Excellent service, timing, and very knowledgeable. Will be using Maxwell Plumbing again in the future and referring others to them."
"Maxwell Plumbing did a fantastic job hooking up our outdoor kitchen. He went above and beyond making us understand what he was doing and why. Communicated throughout the entire project and was reasonable on price."
"Excellent experience including scheduling, communication to service provided. Highly recommend."
"Always professional, kind, and helpful. Our go-to plumber."
Let's Talk
Tell Us About
Your Building.
Whether you're planning a new installation, replacing aging equipment, or dealing with a system that can't keep up with demand — we'll assess your situation and put together an honest recommendation. Commercial estimates are free.
Common Questions
Commercial Water Heater FAQs
Questions we hear from building owners, property managers, and business operators — answered plainly.
Call 360-209-4048 →How do I know if I need a manifolded system or a single large unit? +
What venting is required for commercial gas water heaters? +
Do commercial water heater installations require a permit? +
What is a mixing valve and why does a commercial system need one? +
How is commercial hot water load actually calculated? +
What areas do you serve for commercial work? +
What Customers Say
Trusted by Neighbors Across
SW Washington & Portland
"Aaron was on time and thorough with his explanation of what work would need to be done. He answered all of my questions and went above and beyond by indicating other parts of my plumbing that would benefit from an upgrade. He is honest and thoughtful."
"HONEST, Professional, clean, did great work, super fair price. What more could you ask for?"
"Excellent service, timing, and very knowledgeable. Will be using Maxwell Plumbing again in the future and referring others to them."
"Maxwell Plumbing did a fantastic job hooking up our outdoor kitchen. He went above and beyond making us understand what he was doing and why. Communicated throughout the entire project and was reasonable on price."
"Excellent experience including scheduling, communication to service provided. Highly recommend."
"Always professional, kind, and helpful. Our go-to plumber."
Let's Talk
Tell Us About
Your Building.
Whether you're planning a new installation, replacing aging equipment, or dealing with a system that can't keep up with demand — we'll assess your situation and put together an honest recommendation. Commercial estimates are free.