Clear Installation Plan
We explain the installation requirements, including gas supply and venting.
Tankless Water Heater Installation & Repair In Gaithersburg, MD
Tankless water heater installation, repair, replacement and maintenance in Gaithersburg and the surrounding Maryland area. System sizing, gas supply, venting and descaling explained.
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30+ Years 30+ Years Serving Maryland
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WSSC Licensed WSSC Licensed & Insured
Locally Owned Locally Owned and Operated
Tankless Water Heater Service in Gaithersburg
Tankless water heater installation in Gaithersburg
A tankless water heater has no storage tank. Coils heat the water as it passes through, so hot water is produced on demand rather than kept hot around the clock waiting to be used. Mallick handles tankless water heater installation in Gaithersburg and the surrounding Maryland area, along with repair, replacement and maintenance.
For a household that runs out mid-shower, that difference is the whole point: the supply does not end because a tank has emptied.
Schedule Tankless Water Heater Service
Tell us what you need — we’ll be in touch fast.
Sized For Real Demand
Sized to peak simultaneous demand, with a second unit specified where one genuinely will not cover the house.
Descaled On Schedule
Descaling on a schedule, because Maryland hard water fouls a heat exchanger faster than it kills a tank.
Considering tankless, or lost hot water on one? We compare the installation requirements.
Call (301) 804-6759Worth Knowing
What you gain, and what the install actually involves
Tankless systems offer a smaller footprint, on-demand hot water, and improved energy efficiency when properly sized for the home.
A tankless installation usually requires gas line and venting work. We assess demand and size the system accordingly, including multiple units where needed.
Installation plan
How a tankless call actually runs
Tankless water heater repair is its own skill. A unit that runs cold mid-shower, cycles, or throws a fault code is rarely diagnosed by looking at it, and the fault is usually in the flow sensor, the ignition, the venting or the heat exchanger rather than anywhere obvious.
Maryland's hard water matters more here rather than less. The same scale that shortens a tank's life fouls a tankless heat exchanger, which is why these units want descaling on a schedule. We set that expectation before installation rather than after the first fault, and the maintenance programme exists so it actually gets done.
You call, we answer
You reach a real person, day or night. If you have a fault code on the unit, having it to hand shortens the visit.
Diagnosed or surveyed
For a repair we diagnose on site. For an installation we survey the gas supply and venting.
Installation options
We compare tank and tankless installation requirements so you can understand the work involved.
Warrantied and scheduled
One year on installations, 30 days on repairs, in writing — WSSC permit pulled, and descaling put on a schedule.
Why Mallick
Maryland Has Trusted Mallick For 30+ Years
WSSC-licensed and insured crews, and warranties in writing: one year on installations, 30 days on repairs. The same standard whether it is a tankless water heater call at 2pm or a burst line at 2am.
Google reviews
2,979
4.9 average across Gaithersburg, Frederick and Woodbine
Ways To Save
Current Offers On This Job
$99
Off
Tankless Water Heater Installation
Limit 1 offer per customer, cannot be combined with other offers, residential use only, must be presented at time of service. Not applicable to dispatch charge. Only applies for work performed. Valid Jan 1 – Dec 31, 2026.
$75
Off
Water Heater Replacement
Can be applied to Standard or Tankless Replacement
Limit 1 offer per customer, cannot be combined with other offers, residential use only, must be presented at time of service. Not applicable to dispatch charge. Only applies for work performed. Valid Jan 1 – Dec 31, 2026.
$32
Off
Any Plumbing Service
$1 off for Each Year We’ve Been in Business!
Limit 1 offer per customer, cannot be combined with other offers, residential use only, must be presented at time of service. Not applicable to dispatch charge. Only applies for work performed. Valid Jan 1 – Dec 31, 2026.
Our maintenance plan
The Service Contract Of Choice
A 12-month annual maintenance contract for your home’s plumbing. The team is small enough to give you personalized attention and large enough to handle whatever comes up.
What stands behind every contract
12-month coverage term
24/7 emergency line
Licensed, trained technicians
Payment plans available
2-Year Extended Warranty for Furnished & Installed Equipment
6-Month Repair Warranty
Levels are matched to your home
The office confirms the current contract levels and details before you commit — call and the team will walk you through the options.
12-month term · Sign up by phone
Customer Field Notes
What Customers Remember After The Call
4.9
2,979 Google reviews across three Maryland locations
Field note 01 · Gaithersburg, MD
“Eric and Nick did a wonderful job.”
Very thorough and provided detailed explanation of what was needed to get our garbage disposal up and running.
Abbas and Koli were great technicians.
Quickly diagnosed the issue, thoroughly explained everything, and gave me a few options to move forward. I've had great experiences working with Mallick, highly recommend.
Chrissie Schenkel · Gaithersburg, MD Abbas came to our house for an emergency repair on a Saturday.
He was courteous and kind, he didn’t rush, and he worked hard to fix our problem and thoroughly investigate. It was hard to find a plumber who could do this on a Saturday at the last minute, and we appreciated Mallick’s and Abbas’s willingness.
Raj Nayak · Gaithersburg, MD Abbas Rahimiari was exceptionally professional, looking at our two plumbing problems, describing the underlying issues, fixing one immediately and explaining options on the other. Courteous, clear and efficient. And knowledgeable.
Gordon Schatz · Gaithersburg, MD I had a wonderful experience with Billy.
He was amazing and he was able to fix my issue with no concerns! 10/10! Thank you Billy.
Mia Barker · Gaithersburg, MD Excellent service and support from William Clem and Malick Plumbing.
Had a pinhole leak in a water service line. Found and fixed the problem … thanks so much.
Daryle Seckar · Gaithersburg, MD Roberto and Adelson were great to work with, efficient, and answered all questions. Top service and repair of water heater!
Jonathan Daly · Gaithersburg, MD
Fred and Luka were great!
They took the time to find the issue as well as helping me get opinions on future concerns as a new homeowner! Real experts and will work with them again!
Elijah Wadsworth · Woodbine, MD Abbas and Koli were fantastic.
They quickly identified and resolved our issue, and did a check to ensure there were no other sleeping issues. They were a pleasure to work with, respectful, and kind.
Kelley Barnaby · Gaithersburg, MD I received great service from both Ikem and CJ today.
They quickly identified the leak and fixed the issue. They also did a great job replacing some valves that needed replacing. They were very experienced and efficient. I have used Mallick several times and have always been pleased with their service.
Melissa Cavuto · Gaithersburg, MD Abbas and Erick were professional, knowledgeable and kind.
They inspected and guided me to make safe choices with my range that had a gas leak.
Andrea Huerta · Gaithersburg, MD Abbas and Bryan installed my new water heater.
There was a leak in my furnace and they fixed it also! The job was perfect. They had to install vents that were well done. They left no trace and the house was completely clean. The new water heater works like a charm. HIGHLY RECOMMEND this team and Mallick.
Janet · Gaithersburg, MD Kyle was so helpful in helping my husband and I fix the water pressure in our house. Kyle was very well versed and experienced, providing great options for future improvements to water filtering. I would highly recommend his services to anybody struggling with plumbing issues.
Azusena Herrera Tapia · Gaithersburg, MD
Every quote above comes directly from Mallick’s current Google Business Profile record.
Read more customer storiesCommon Questions
Tankless Water Heater Questions, Answered
Still Stuck?
Talk To A Plumber
(301) 804-6759Someone picks up 24/7 — nights, weekends, and holidays included.
What does it mean that Mallick Plumbing is a Rinnai ACE Pro?
ACE stands for Advanced Comfort Expert. Mallick Plumbing & Heating is part of Rinnai's ACE PRO network, whose professionals receive Rinnai product training for installation and service. For your home, that means you can discuss Rinnai tankless options, installation requirements and ongoing maintenance with our team before choosing a system.
What are the benefits of switching to a tankless water heater?
Tankless systems provide on-demand hot water, a smaller footprint and improved energy efficiency. Installation may require gas line and venting changes.
Are tankless water heaters suitable for large households?
Yes. For a high-demand household we size the unit to peak simultaneous use, and where a single unit genuinely will not cover it we will specify more than one rather than install something that disappoints in the first week. The sizing conversation happens before work begins, not after the install.
What are the signs a tankless water heater needs repair?
Running cold partway through a shower, cycling between hot and cold, reduced flow, or an error code on the unit. Those usually point at the flow sensor, ignition, venting or a scaled heat exchanger. Because tankless units self-diagnose to a code, getting the code to us on the phone often shortens the visit.
How often does a tankless water heater need descaling?
Annually in this area, and it is not optional maintenance the way an annual tank flush arguably is. Maryland's hard water scales the heat exchanger, and a fouled exchanger loses efficiency first and fails second. Descaling is part of our maintenance programme for exactly that reason.
Do I need a permit to install a tankless water heater?
Gas appliance work in Montgomery and Prince George's County requires a WSSC permit and inspection, and it cannot legally be done by the homeowner — it has to be a WSSC-licensed plumber or gasfitter. That applies to a tankless conversion as much as to a tank replacement, and we pull the permit as part of the job.
Where We Work
Tankless Water Heater Service Across Maryland
Bethesda Rockville Silver Spring Germantown Potomac Olney Clarksburg Damascus Chevy Chase North Potomac Frederick Woodbine Columbia Ellicott City Aspen Hill Boyds Burtonsville Darnestown North Bethesda Poolesville Takoma Park Wheaton–Glenmont White Oak Green Valley Linganore Washington, DC College Park
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