Tankless Water Heater Service in Northeast Texas

A tankless unit that flashes a code, or runs hot then cold, is usually scale, a sensor, or a vent. Underwood repairs, flushes, and installs tankless water heaters across Collin, Grayson, Fannin, Hunt, and Lamar counties.

Tankless Unit Down? Call and We'll Schedule a Tech.

Note the code on the display if there is one, then call (903) 449-1677. Evenings included.

Our Tankless Service Process

Call or request a quote: The code, the brand if you know it, and whether this is a repair or a new install.

Read the unit: Error code, vent, gas supply, and scale. We don’t replace a heat exchanger for a dirty filter.

Explain the fix: A flush, a part, or a new unit. You hear it before we order the expensive piece.

Service it: Descale, sensor, or igniter, with the parts we carry for the units we see most.

Fire it under load: A tap open long enough to prove it holds temperature, not a five-second test.

Leave the valves labeled: Service valves left so the next flush doesn’t start from scratch.

The Underwood Water Heater Standard

Do you service every tankless brand?

We repair and install the tankless units we see across this region. Tell us the brand when you call so we bring the right board and sensor.

How often should a tankless unit be flushed?

In this water, yearly is the number we give most houses. Hard-water homes that skip it are the ones calling with a code.

Can you convert my tank unit to tankless?

When the gas line and the vent can carry it. We’ll look before we promise the closet can take the change.

Where do you install tankless heaters?

Collin, Grayson, Fannin, Hunt, and Lamar counties, from McKinney, Bonham, and Sherman. Same-week on most flushes, scheduled installs for conversions.

Can I finance a tankless install?

Yes, subject to credit approval. A flush is a service call. A new unit is a financing conversation. See the Financing page.

Why Underwood

Why Northeast Texas Calls Underwood for Tankless Service.

We Communicate.

We read the code and tell you what it means. You don’t need a forum thread and a cold shower.

Stocked Trucks, One Trip.

Flush kits and the sensors we replace most are on the van, so a code doesn’t automatically mean a parts delay.

Plumbing and Septic, One Call.

If the unit is fine and the recirculation pump or the gas supply isn’t, we still fix it. Plumbing is the rest of what we do.

Seasoned Service Professionals

Nexstar trained techs, licensed plumbers, TCEQ registered.

What We Fix

Tankless Repair and Installs, Start to Finish

Error codes: read and traced, not cleared and hoped on.
Descaling: a real flush through service valves, not a vinegar bottle poured in the top.
Igniters and sensors: replaced when the code and the test say that part failed.
Venting: checked when the unit lights and then locks out.
New installs: sized for the house, with service valves so the next flush is possible.
Tank-to-tankless: gas and vent confirmed before the old tank comes out.

Financing Available

We offer flexible payment options for our services.

Signs It's Time to Call for Tankless Service

A code on the display that won't clear.
Water that runs hot, then cold, then hot.
The unit is loud, or it bangs when a tap opens.
It hasn't been flushed since it was installed.
Lukewarm water when two showers run.
A smell of gas, or a vent that looks loose. If you smell gas, leave and call 911, then call us.

Tankless service in McKinney, Allen, Prosper, Sherman, Denison, Bonham, and Greenville.

Reviews

Don’t Take Our Word for It. What Our Customers Say.

Reviews

4.9

(1521 Reviews)

    
 
 
         
   Michael Jeter 
 
 
 
 Trustindex verifies that the original source of the review is Google. Plumber knew his job and how to fix the problem fast.
  
 
        
   Sheldon Nicolle 
 
 
 
 Trustindex verifies that the original source of the review is Google. Chad came by and did an amazing job. Peace of mind is a valuable thing. Thanks Underwood!!
  
 
        
   Saphir Butter 
 
 
 
 Trustindex verifies that the original source of the review is Google. I needed a sewer tank cover replaced due to it being hit by the lawnmower. These guy fixed it in less than 30 minutes.
Chad also suggested putting landscaping stuff around the 4 tanks to prevent this happening again. Totally happy with their service.
  
 
        
   Sally May 
 
 
 
 Trustindex verifies that the original source of the review is Google. Great

More Services

We Solve Every Plumbing and Septic Problem.

Plumbing

Repairs, repipes, and installs for every fixture and line in the house.

Septic Service

Inspections, repairs, and installs for tanks and drain fields.

Septic Pumping

Scheduled and emergency pump outs, with a digital report after each visit.

Emergency Plumbing

Burst pipes and backups. We pick up nights, evenings, and holidays.

Sewer

Camera inspection, spot repair, and full sewer line replacement.

Drain

Clogs cleared and hydro jetting that keeps them from coming back.

Water Heater

Tank and tankless repair and replacement.

Water Quality

Filtration, softening, and testing for clean water at every tap.

Commercial Plumbing

Restaurants, shops, and offices kept running with minimal downtime.

Water Line Repair

Leak location, spot repair, and full water line replacement.

Protect Your Home

Generous Membership Plans.

At Underwood, we offer tailored solutions to keep your home and its systems running smoothly. Whether you need memberships to be county compliant or simply maintain your systems for the long haul, we have a plan to fit your needs.

Get in Touch

Ready to Get the Tankless Unit Fixed?

Tell us what’s going on and where and we’ll get a licensed tech out to you ASAP.

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(903) 449-1677

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Service Areas

Tankless Service Across Northeast Texas and DFW.

We run out of four offices in McKinney, Bonham, and Sherman.

Counties We Cover

Tankless repairs and installs across Collin, Hunt, Grayson, Fannin, Lamar, and Cooke counties from McKinney, Bonham, and Sherman. Bryan County, Oklahoma is septic maintenance only. We are not licensed to plumb there.

Not sure whether you’re in range? Call (903) 449-1677. Related work: Water Heater Repair and Water Heater Replacement.