Thinking of Going Tankless? Fix Your Water First
There is no clean winner between tank and tankless. A tank is reliable and proven. A tankless is excellent and gives you unlimited hot water, but it is sensitive to hard water, and even treated city water can be too hard for one. If you go tankless without a softening system, you are setting up the failure yourself.
Every homeowner eventually asks their plumber the same question. Tank or tankless?
I asked mine on the podcast, expecting a recommendation. What I got instead was refreshing, because he refused to give me one.
“A lot of customers then proceed to ask me if they want tanks or if they want tankless hot water heaters. And I have, there’s no real easy answer for that. There’s two avenues of thought.”
Zach is a licensed plumber and he has worked on my house since 2023. He has no product to move and no brand deal, which is exactly why his answer is worth reading. The interesting part of the conversation was not which one wins. It was the thing almost nobody does before switching, and the reason their expensive new unit disappoints them.
Why do hot water tanks fail?
Start with what is probably in your basement right now, because it is one of the most common calls Zach gets.
“The water tanks. Hot water tanks that hold water tend to rupture a lot because they’re under pressure.”
That is the tradeoff of the design. A tank works by holding a large volume of hot water under pressure, ready to go. It is simple and it is reliable, and the same thing that makes it work is the thing that eventually ends it. When it goes, everything it was holding ends up on your floor.
Tank vs tankless: what you are actually choosing between
Zach’s framing is that these are two legitimate schools of thought, not an old option and a correct one.
“You can have a holding tank full of hot water. It holds it. It’s reliable. It’s been working for hundreds of years. The tankless is a fantastic piece of machinery. It’s very, very, very good. It’s unlimited hot water. It’s just, it’s a little sensitive.”
| Consideration | Hot water tank | Tankless |
|---|---|---|
| How it works | Holds a volume of hot water under pressure, ready to use | Heats water on demand as it passes through |
| Supply | Finite. When the tank is drained, you wait | Unlimited hot water |
| Track record | Proven over a very long time. Reliable | Excellent machinery, more recent, more sensitive |
| Main failure mode | Rupture, because it is holding water under pressure | Damage from untreated hard water |
| Water quality | More forgiving | Sensitive. Even treated city water can be too hard |
| What it needs from you | Yearly maintenance and eventual replacement | Water treatment as part of the install, not later |
Notice what is not in that table: a winner. Zach genuinely likes tankless. He calls it fantastic and means it. He just will not tell you it is the right call for your house without knowing what comes out of your tap.
The mistake almost everybody makes
This is the part worth the whole conversation.
“And what most people don’t understand is that they’ll replace their hot water tank with the tankless without treating their current water supply. Even treated city water can be a little too hard for those. So if you’re going tankless, get a softening system.”
Read that again, because it undoes an assumption most of us are carrying. You are on city water. You assume city water is treated, therefore fine. It is treated. It can still be too hard for a tankless unit.
Swapping a tank for a tankless is not like swapping a fridge. The new unit is more sensitive than the thing it replaced, so the water that was good enough for your tank may not be good enough for it. Treat the water as part of the job. Discovering it afterward means paying twice.
So the honest sequence is not “pick tankless, install tankless.” It is:
What is a softener actually doing?
It is dealing with what is dissolved in your water, mostly calcium and other minerals. That mineral content is what “hard” means, and it is what a sensitive appliance objects to over time.
The reason Zach keeps pushing the test rather than just naming a product is that hardness is local and specific. What your neighbourhood needs and what a house twenty minutes away needs are not automatically the same, and the equipment gets sized to the answer.
Are reverse osmosis systems worth it?
I asked, because these are everywhere now. Zach has installed hundreds of them and he likes them.
“I think they’re fantastic. Reverse osmosis water is good. Just be careful what products you buy.”
The caution is about where the thing came from, not the technology.
“Because if you buy a lot of the reverse osmosis systems off of Amazon, they come with little plastic clips. Microplastics get into those waters.”
His advice is to go to a local supplier instead, and the reasoning is practical rather than snobbish:
You can get the replacement parts. A system you cannot service is a system you throw away.
The parts are to code.
It is warrantied.
This is a theme he came back to repeatedly across the whole episode, and it is not only about water. The same logic applied to the sump pit in my own basement, which had a design flaw that a supplier-bought part would not have had. Cheap online equipment tends to be undersized, oddly designed, and made of plastic where a supplier’s version is brass or metal. Those subtle differences, in his words, add to the length of your system’s life.
There is no universal winner between tank and tankless.
Going tankless? Test your water and budget for a softener as part of the job.
Being on city water does not mean your water is soft enough.
Buy water equipment from a supplier, not a marketplace listing.
Why I think this is worth knowing before you list
I sell houses in Toronto and York Region, and hot water is one of those things that only becomes a conversation at the worst possible moment. Either it ruptures, or a buyer’s inspector flags the age of it, or someone installs a beautiful tankless unit in a house with hard water and quietly starts having problems with it a year later.
The version of this that costs you nothing is the water test. It is the cheapest step in the entire decision and it is the one that determines whether the expensive step works.
And if you take one thing from Zach across this whole episode, it is that the honest tradespeople are the ones who tell you the answer depends. The ones with an instant recommendation and an iPad and no tools are, in his words, salesmen in boots.
Frequently Asked Questions About Tank vs Tankless
Is tankless better than a hot water tank?
Do I need a water softener for a tankless water heater?
How do I know what water softener I need?
Why do hot water tanks fail?
Are reverse osmosis systems worth it?
Related Reading
- What a Home Inspector Actually Looks For, including what the decade your house was built predicts about its plumbing.
- Property Maintenance Checklists, for the yearly service that keeps mechanical systems from surprising you.
- Renovations That Pay Off, for where your money actually comes back on a sale.
Watch the Full Episode
This is from my conversation with Zach, a licensed plumber, on Supply and Demand. He also gets into the backup sump pump most people do not know they have, the wet spot on my kitchen ceiling that was never a leak, and the $100,000 mistake he made himself before he was licensed. Listen on Apple Podcasts or Spotify.
If you are buying or selling in Toronto or York Region and want to talk through what is worth doing to a house before it goes on the market, I am happy to point you in the right direction.
Written by Adam Nadler, a licensed REALTOR serving Toronto and York Region with RE/MAX Your Community Realty, Brokerage. Nothing here is plumbing or building code advice. Product opinions are Zach’s own and are not endorsements by Vision Real Estate. Always hire a licensed technician.