Why Does My Tankless Water Heater Sometimes Run Cold?
Tankless water heaters are designed to give you endless hot water on demand. But if you’ve ever been in the middle of a shower in your Auburn home and suddenly felt an icy blast, you know that’s not always the case. It’s frustrating and disruptive—but the good news is, most of the time, there’s a simple explanation.
At 2 Sons Plumbing and Sewer Auburn, we get calls about this issue all the time. In many cases, it comes down to maintenance or minor adjustments, not a major system failure.
Why Tankless Water Heaters Go Cold
If your water heater works fine one day and cuts out the next, here are the most common culprits we see in Auburn homes:
Low Water Flow
Tankless units need a minimum flow of water to activate the heating element. If you’re only running a trickle, the heater may shut off, leaving you with cold water.
Mineral Buildup
Hard water in Auburn leaves behind mineral deposits that settle inside the heat exchanger. Over time, this buildup slows efficiency and makes the unit inconsistent.
Thermostat Problems
Sometimes the solution is as easy as checking your settings. If your unit is set below 120°F, the water may never feel fully hot.
High Demand
Running multiple fixtures at once—like a shower, dishwasher, and washing machine—can push a tankless heater past its limit. When demand spikes, you may notice sudden temperature swings.
Quick Fixes You Can Try
Before calling in a plumber, here are a few safe steps you can try yourself:
- Run another fixture. Tankless heaters often perform better with steady flow.
- Check the thermostat. Make sure it’s set to at least 120°F.
- Flush the system. If it’s been more than a year since your last flush, mineral buildup could be causing the problem. Using a vinegar flush kit may help if you’re comfortable doing it yourself.
When to Call a Plumber
Not every tankless issue can be fixed with a quick DIY step. Shut the system down and call 2 Sons Plumbing and Sewer Auburn if:
- You see error codes you don’t understand
- You smell gas near the heater
- The water never heats up no matter what you do
Our licensed plumbers can descale your system, replace faulty parts, check venting and gas connections, and make sure your unit is running safely.
Typical Costs in Auburn
Professional descaling service: $250–$500
Other repairs: Costs vary depending on the issue
Get Back to Reliable Hot Water
Cold surprises in the middle of a shower are frustrating, but they’re rarely permanent. Most tankless water heater problems can be fixed quickly once the cause is identified.
At 2 Sons Plumbing and Sewer Auburn, we’ll inspect your system, explain what’s going on in plain language, and get it working the way it should. Whether it’s a simple flush or a repair, we’ll make sure you can rely on hot water again.
Call us today at (206) 487-1757 for tankless water heater service in Auburn. We’ll track down the issue, fix it fast, and keep the hot water flowing in your home.
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!
Services Provided:
PLUMBING:
SEWER :