Why Does My Tankless Water Heater Go Cold in the Shower?
There’s nothing worse than finally stepping into a warm shower, only to get blasted with freezing water a few minutes later. If your tankless water heater keeps going cold mid-shower, you’re not the only one dealing with it—many Bellevue homeowners run into the same frustrating problem.
At 2 Sons Plumbing and Sewer Bellevue, our licensed plumbers know exactly how to diagnose and fix these problems, restoring reliable hot water to your home.
We’ve helped families enjoy dependable hot water again with professional tankless water heater repair and maintenance.
Tankless Water Heater Goes Cold in the Shower? Here’s Why
There are several reasons your tankless water heater may suddenly switch from hot to cold:
- Low water flow – Tankless units need a certain minimum flow to keep the burners running. If the flow dips, the heat shuts off.
- Mixing valve issues – A faulty mixing valve can interfere with temperature regulation.
- Scale buildup – Over time, mineral deposits from Bellevue’s water supply can clog the system and reduce efficiency.
Most of the time, it’s not a sign that your system is failing—it just needs maintenance or a small repair.
DIY Steps Bellevue Homeowners Can Try
Before you pick up the phone to call a plumber, there are a few simple things you can safely try on your own first:
- Run more water – Make sure the flow is strong enough for the unit to fire properly.
- Check your settings – Adjust the unit to around 120°F, which is safe and effective.
- Descale annually – Flushing out mineral deposits once a year helps prevent buildup and keeps hot water flowing steadily.
If these steps don’t solve the problem, or if you see error codes flashing on your system, it’s best to get a professional inspection.
When to Call a Tankless Water Heater Expert in Bellevue
There are situations where DIY fixes aren’t enough. Call 2 Sons Plumbing and Sewer Bellevue right away if:
- You smell gas near the unit
- The heater displays error codes you don’t recognize
- Descaling or temperature adjustments don’t solve the issue
Professional tankless water heater descaling usually costs $250–$500. Valve repairs or replacements vary depending on the part, but taking care of issues early can save you from costly breakdowns and extend the life of your system.
Why Bellevue Homeowners Choose 2 Sons Plumbing and Sewer
- Experience You Can See – Our licensed plumbers have spent years repairing and maintaining tankless water heaters throughout Bellevue.
- Know-How That Matters – From older models to the latest systems, we understand how each brand works and how to fix issues fast.
- Trusted in the Community – Local families know us as a go-to plumbing company with a track record of reliable results.
Call 2 Sons Plumbing and Sewer Bellevue Today
Don’t let cold showers become part of your daily routine. Call 2 Sons Plumbing and Sewer Bellevue today at (206) 487-1757 for fast, professional tankless water heater repair and maintenance. From routine descaling to valve repairs, we’ll make sure your system delivers steady hot water when you need it most.
Tina Tantoco
1 month ago
UPDATE: Adam returned to do the repair work for a leak in my crawlspace. He was timely with his arrival, inspected the area, and very clear about cost and the work he would be performing. He worked efficiently and tested thoroughly when he was done. Very happy with the service that I got both days with 2Sons Plumbing and will definitely call them again if needed and recommend them to others.
Riley did an excellent job helping me to diagnose an issue with a pipe in my crawlspace. It was a difficult space to navigate through, but he was able to get photos and videos then talk through a game plan and confirm a path forward. I very much appreciated his help and guidance. I would definitely call him back if I need more work done
Riley did an excellent job helping me to diagnose an issue with a pipe in my crawlspace. It was a difficult space to navigate through, but he was able to get photos and videos then talk through a game plan and confirm a path forward. I very much appreciated his help and guidance. I would definitely call him back if I need more work done
Tina Tantoco
1 month ago
UPDATE: Adam returned to do the repair work for a leak in my crawlspace. He was timely with his arrival, inspected the area, and very clear about cost and the work he would be performing. He worked efficiently and tested thoroughly when he was done. Very happy with the service that I got both days with 2Sons Plumbing and will definitely call them again if needed and recommend them to others.
Riley did an excellent job helping me to diagnose an issue with a pipe in my crawlspace. It was a difficult space to navigate through, but he was able to get photos and videos then talk through a game plan and confirm a path forward. I very much appreciated his help and guidance. I would definitely call him back if I need more work done
Riley did an excellent job helping me to diagnose an issue with a pipe in my crawlspace. It was a difficult space to navigate through, but he was able to get photos and videos then talk through a game plan and confirm a path forward. I very much appreciated his help and guidance. I would definitely call him back if I need more work done
Tyler Gunter
2 months ago
I had a phenomenal experience with Carey, Carson, Cody, and Salvador! I had them install a new dedicated line to a water hydrant in my yard and it the project turned out perfectly! I want to especially commend Casey for going out of the way to figure out the best way to achieve what I wanted (he actually suggested the hydrant after considering what I wanted in my project). He worked professionally to give me the best possible quote he could for the project and saved me some serious $$! They trenched a 60ft 22 inch deep trench, ran the pipe, and put all the pavers back on my patio and the job site was perfectly clean when they were done.
All of them worked insanely hard over 2 days to do the trench since there were a ton of rocks in my yard which wasn’t known just how difficult it would be at the time. Instead of charging me more they just finished the project to completion.
I would recommend them to anyone looking for an excellent experience for plumbing work! I’ve already told several people what a great and difficult job they did!
All of them worked insanely hard over 2 days to do the trench since there were a ton of rocks in my yard which wasn’t known just how difficult it would be at the time. Instead of charging me more they just finished the project to completion.
I would recommend them to anyone looking for an excellent experience for plumbing work! I’ve already told several people what a great and difficult job they did!
Tyler Gunter
2 months ago
I had a phenomenal experience with Carey, Carson, Cody, and Salvador! I had them install a new dedicated line to a water hydrant in my yard and it the project turned out perfectly! I want to especially commend Casey for going out of the way to figure out the best way to achieve what I wanted (he actually suggested the hydrant after considering what I wanted in my project). He worked professionally to give me the best possible quote he could for the project and saved me some serious $$! They trenched a 60ft 22 inch deep trench, ran the pipe, and put all the pavers back on my patio and the job site was perfectly clean when they were done.
All of them worked insanely hard over 2 days to do the trench since there were a ton of rocks in my yard which wasn’t known just how difficult it would be at the time. Instead of charging me more they just finished the project to completion.
I would recommend them to anyone looking for an excellent experience for plumbing work! I’ve already told several people what a great and difficult job they did!
All of them worked insanely hard over 2 days to do the trench since there were a ton of rocks in my yard which wasn’t known just how difficult it would be at the time. Instead of charging me more they just finished the project to completion.
I would recommend them to anyone looking for an excellent experience for plumbing work! I’ve already told several people what a great and difficult job they did!
Kirsten Nakayama
2 months ago
We cannot recommend 2 Sons Plumbing and Sewer enough - they were the only company out of 5 I had contacted that could come out the same day. Our plumber, Jacob, was polite, thoughtful, and very knowledgeable. He quickly diagnosed the issue and shared several options to fit within our budget and did his best to keep our costs down. Great guy and great service!
Kirsten Nakayama
2 months ago
We cannot recommend 2 Sons Plumbing and Sewer enough - they were the only company out of 5 I had contacted that could come out the same day. Our plumber, Jacob, was polite, thoughtful, and very knowledgeable. He quickly diagnosed the issue and shared several options to fit within our budget and did his best to keep our costs down. Great guy and great service!
Aditya Mahadevan
2 months ago
Carey did an amazing job diagnosing and fixing a water leak which started in my bathroom and seeped into the garage below. He came within an hour or two after I called the company, right after his previous job. He was fast, friendly and informative. He even helped me find my water main in case I need it for future. Definitely calling this company if I need help with a water/plumbing emergency in future.
Aditya Mahadevan
2 months ago
Carey did an amazing job diagnosing and fixing a water leak which started in my bathroom and seeped into the garage below. He came within an hour or two after I called the company, right after his previous job. He was fast, friendly and informative. He even helped me find my water main in case I need it for future. Definitely calling this company if I need help with a water/plumbing emergency in future.
Natalie Page
2 months ago
This was my second time using 2 Sons plumbing. I received a call about scheduling the appointment for the next day. Jake was very professional. He explained my choices for the service and didn't push the most expensive option. Even though the scope of the job changed during the visit it was completed that same day. He did a good job and cleaned up the worksite. Would definitely recommend.
Natalie Page
2 months ago
This was my second time using 2 Sons plumbing. I received a call about scheduling the appointment for the next day. Jake was very professional. He explained my choices for the service and didn't push the most expensive option. Even though the scope of the job changed during the visit it was completed that same day. He did a good job and cleaned up the worksite. Would definitely recommend.
Amber Rhodes
4 months ago
I had a great experience with 2 Sons Plumbing and Sewer. I scheduled an appointment online last night, and they called me first thing this morning. Natalie was so kind and even offered me an earlier appointment that same day, which I really appreciated.
Justin came out and was friendly, professional, and honest. He gave me a fair estimate for the repair I needed and also provided estimates for a few additional code-related fixes that may need to be addressed in the future. I never felt pressured to approve any extra work, which I really appreciated.
From scheduling to the service visit, the entire experience was easy and professional. I would definitely use 2 Sons Plumbing and Sewer again and would happily recommend them to others!
Justin came out and was friendly, professional, and honest. He gave me a fair estimate for the repair I needed and also provided estimates for a few additional code-related fixes that may need to be addressed in the future. I never felt pressured to approve any extra work, which I really appreciated.
From scheduling to the service visit, the entire experience was easy and professional. I would definitely use 2 Sons Plumbing and Sewer again and would happily recommend them to others!
Amber Rhodes
4 months ago
I had a great experience with 2 Sons Plumbing and Sewer. I scheduled an appointment online last night, and they called me first thing this morning. Natalie was so kind and even offered me an earlier appointment that same day, which I really appreciated.
Justin came out and was friendly, professional, and honest. He gave me a fair estimate for the repair I needed and also provided estimates for a few additional code-related fixes that may need to be addressed in the future. I never felt pressured to approve any extra work, which I really appreciated.
From scheduling to the service visit, the entire experience was easy and professional. I would definitely use 2 Sons Plumbing and Sewer again and would happily recommend them to others!
Justin came out and was friendly, professional, and honest. He gave me a fair estimate for the repair I needed and also provided estimates for a few additional code-related fixes that may need to be addressed in the future. I never felt pressured to approve any extra work, which I really appreciated.
From scheduling to the service visit, the entire experience was easy and professional. I would definitely use 2 Sons Plumbing and Sewer again and would happily recommend them to others!
Jackie Johanson
5 months ago
⭐⭐⭐⭐⭐
I had a project that required a quick turnaround for some temporary top-out plumbing, and Two Sons Plumbing was incredibly responsive from the start. They came out quickly to provide a quote and, even during what I know is their peak season, they prioritized getting my project scheduled. That level of customer service was greatly appreciated.
The quote was a bit of sticker shock, but that’s simply the reality of the Seattle market—not a reflection of their service. What really stood out was that the same person who came out to provide the estimate also completed the work. It meant I didn’t have to explain everything twice, and we’d already built a level of trust before the job even started.
The quality of the work was excellent, and they even went above and beyond by replacing a damaged toilet lid at no extra charge. Small gestures like that make a big difference.
If you’re looking for a fast, reliable plumbing company that does quality work and takes great care of its customers, I’d definitely recommend Two Sons Plumbing.
I had a project that required a quick turnaround for some temporary top-out plumbing, and Two Sons Plumbing was incredibly responsive from the start. They came out quickly to provide a quote and, even during what I know is their peak season, they prioritized getting my project scheduled. That level of customer service was greatly appreciated.
The quote was a bit of sticker shock, but that’s simply the reality of the Seattle market—not a reflection of their service. What really stood out was that the same person who came out to provide the estimate also completed the work. It meant I didn’t have to explain everything twice, and we’d already built a level of trust before the job even started.
The quality of the work was excellent, and they even went above and beyond by replacing a damaged toilet lid at no extra charge. Small gestures like that make a big difference.
If you’re looking for a fast, reliable plumbing company that does quality work and takes great care of its customers, I’d definitely recommend Two Sons Plumbing.
Jackie Johanson
5 months ago
⭐⭐⭐⭐⭐
I had a project that required a quick turnaround for some temporary top-out plumbing, and Two Sons Plumbing was incredibly responsive from the start. They came out quickly to provide a quote and, even during what I know is their peak season, they prioritized getting my project scheduled. That level of customer service was greatly appreciated.
The quote was a bit of sticker shock, but that’s simply the reality of the Seattle market—not a reflection of their service. What really stood out was that the same person who came out to provide the estimate also completed the work. It meant I didn’t have to explain everything twice, and we’d already built a level of trust before the job even started.
The quality of the work was excellent, and they even went above and beyond by replacing a damaged toilet lid at no extra charge. Small gestures like that make a big difference.
If you’re looking for a fast, reliable plumbing company that does quality work and takes great care of its customers, I’d definitely recommend Two Sons Plumbing.
I had a project that required a quick turnaround for some temporary top-out plumbing, and Two Sons Plumbing was incredibly responsive from the start. They came out quickly to provide a quote and, even during what I know is their peak season, they prioritized getting my project scheduled. That level of customer service was greatly appreciated.
The quote was a bit of sticker shock, but that’s simply the reality of the Seattle market—not a reflection of their service. What really stood out was that the same person who came out to provide the estimate also completed the work. It meant I didn’t have to explain everything twice, and we’d already built a level of trust before the job even started.
The quality of the work was excellent, and they even went above and beyond by replacing a damaged toilet lid at no extra charge. Small gestures like that make a big difference.
If you’re looking for a fast, reliable plumbing company that does quality work and takes great care of its customers, I’d definitely recommend Two Sons Plumbing.
Brad Poirier
5 months ago
Had a great experience with 2 Sons Plumbing and Sewer and the representative they sent, Jake. They did a fantastic job communicating through email, text, and calls, sending reminders when the appointment was and who their representative was, and when he would arrive. Jake did a wonderful job hunting done where the leak was coming from and explaining the options I had for getting the leak repaired. When he left he emailed my receipt, pictures he had taken of my water lines under the house, and the options I could use to compete locating and repairing the leak. Highly recommend them. A very professional outfit.
Brad Poirier
5 months ago
Had a great experience with 2 Sons Plumbing and Sewer and the representative they sent, Jake. They did a fantastic job communicating through email, text, and calls, sending reminders when the appointment was and who their representative was, and when he would arrive. Jake did a wonderful job hunting done where the leak was coming from and explaining the options I had for getting the leak repaired. When he left he emailed my receipt, pictures he had taken of my water lines under the house, and the options I could use to compete locating and repairing the leak. Highly recommend them. A very professional outfit.
Jennifer Suemnicht
7 months ago
I asked some of my real estate colleagues who people have been using for plumbing repairs lately and several said “2 Sons”! So friendly and responsive. Came out right away for an estimate, had the best follow up, came in with the best price, and got me on the schedule and got the work done on the very next day! Everyone I spoke with was friendly and fantastic! Highly recommend!
Jennifer Suemnicht
7 months ago
I asked some of my real estate colleagues who people have been using for plumbing repairs lately and several said “2 Sons”! So friendly and responsive. Came out right away for an estimate, had the best follow up, came in with the best price, and got me on the schedule and got the work done on the very next day! Everyone I spoke with was friendly and fantastic! Highly recommend!
Katy Garner
8 months ago
We had a mystery leak per our meter reading. Riley and Riley saved the day. They promptly discovered the issue, resolved and repaired our pipes in one service call. They were quick, thorough and entirely delightful. They took the time to talk me through the job. I felt heard, safe and comfortable with the two of them in my house. For my next plumbing disaster I hope to get ‘The Riley’s’; but know, whoever comes will be excellent. Thanks 2 Sons!
Katy Garner
8 months ago
We had a mystery leak per our meter reading. Riley and Riley saved the day. They promptly discovered the issue, resolved and repaired our pipes in one service call. They were quick, thorough and entirely delightful. They took the time to talk me through the job. I felt heard, safe and comfortable with the two of them in my house. For my next plumbing disaster I hope to get ‘The Riley’s’; but know, whoever comes will be excellent. Thanks 2 Sons!
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