Reuben's Home Inspection Blog


Hot Water At My Kitchen Sink 450% Faster

HourglassDo you ever get annoyed with how long it takes to get hot water at your kitchen sink?  I do did, up until last weekend.  It used to take a full 45 seconds with the hot water turned on full blast before I would actually get hot water my kitchen faucet.   With my kitchen faucet rated at 2.2 gallons per minute, that would equal a little over 1 1/2 gallons of wasted water every time I needed hot water at the sink.

I've considered a few different options to get hot water at my kitchen sink faster, such as installing a re-circulating pump or a point-of-use water heater - you can read about the details of these options at Home Depot's web site.   I decided against these options because the installation would take too much time, and the materials alone would cost more than I was willing to spend.  Thanks to an idea I read about in The Journal of Light Construction, I was able to significantly reduce the amount of time it takes to get hot water at my kitchen faucet, and the total cost of materials for this project was less than $40.

All I did was install a dedicated 3/8" water supply line from the water piping coming off the top of my water heater to the kitchen sink faucet.  By installing this 3/8" water line, I've cut the wait time from 45 seconds down to 10 seconds.   Part of the reason I get hot water so much faster is that the hot water doesn't need to fill up all of the main 'branch' lines to get to my kitchen faucet.  The hot water line that feeds my kitchen sink consists of 17' of 3/4" tubing, then another 25' of 1/2" tubing.   I've cut the total run down to about 25' by running the line straight to my faucet.  The other reason this works is because a 3/8" tube has about 25% of the volume as a 3/4" tube.

You might think that this reduction in size would equate to lower water flow at the kitchen faucet, but it actually made no noticeable difference.  The hot and cold water flow both seem to be identical.   So what's the downside to this, and why don't more plumbers do this?  It's a code violation.  The Minnesota State Plumbing Code requires a minimum of 1/2" pipe to the kitchen sink.  Because of this, I left the old 1/2" water line in place.  When it comes time for me to sell my house, I'll probably just re-connect the old 1/2" water line to the faucet.  It should take about 30 seconds.

Reuben Saltzman, Structure Tech Home Inspections


Comment balloon 13 commentsReuben Saltzman • May 29 2012 03:24AM


I have understood that these pumps should be on the furthest faucet from the water heater, but if you have two areas serviced by different lines you need two pumps.

I have also understood that if you have a gas water tank it causes the tank to fire more frequently.  That I have not been able to find proof for.

But, silly, you only have to move your kitchen closer to the water heater!  You silly.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) almost 8 years ago

Reuben, very interesting information. Thanks for sharing today.

Posted by David Burrows, No Pressure, Just Seriously Devoted to Real Estate (Classic Realty) almost 8 years ago

Reuben, thanks for illuminating a very interesting solution to a very common problem

Posted by Chris Smith, South Simcoe, Caledon, King, Orangeville Real Esta (Re/Max Chay Realty Inc., Brokerage) almost 8 years ago

Which is one reason why PEX with a manifold system is so much bettter. 

Posted by James Quarello, Connecticut Home Inspector (JRV Home Inspection Services, LLC) almost 8 years ago

Someone just told me about a recirculating pump for a shower which I am definitely going to look into! It will be more expensive than your option but I think it will be worth it.

Posted by Peggy Chirico, REALTOR® 860-748-8900, Hartford & Tolland County Real Estate (Prudential CT Realty) almost 8 years ago

Reuben, do you know about thermosyphon loops?  If you have a basement you can have hot water at remote locations----works the same as a mechanical re-circulation loop but without the pump.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 8 years ago

Jay - that's my understanding as well, and it makes sense.  As for the water heater having to fire more often, yes, because you have a long tube of uninsulated water, which will cause the water to cool faster.  I don't think it would be enough to ever notice a difference in your gas bill though.

As for moving my kitchen... duh!  Why didn't I thinkof that.  How about just moving my water heater in to the kitchen instead?  Classy!

David- thanks for reading.

Chris - I was quite happy with the results.  I just had to share.

James - definitely.  I re-plumbed my sisters entire house with PEX using home runs... I should find out how long it takes her to get hot water at the kitchen sink.

Peggy - you hate that wait at the shower, huh?

Charles - I'm familiar with those, but it seemed like more work to set one of those up, and I wasn't as sure that it would work as well.  

One other interesting solution I've heard about is a system that somehow pumps the not-so-hot water back in to the cold water supply until the water gets warm enough, then starts delivering hot water out of the kitchen faucet.  I've only heard about this system though; never read about it, and I don't fully understand how this would work.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) almost 8 years ago

Mine works awesome---the only real cost is the length of copper back to the heater

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) almost 8 years ago

Reuben, I will not snitch on you ; ) Interesting solution though on the hot water delay. I am assuming you must have easy access under your kitchen.


Posted by Donald Hester, NCW Home Inspections, LLC (NCW Home Inspections, LLC) almost 8 years ago

Charles - I assume you insulated the hot water lines?  

Donald - yes, my basement is completely unfinished.  It was a piece of cake. 

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) almost 8 years ago

I love reading about stuff like this. Why undo it when you sell?

Posted by Greg Nino, Houston, Texas (RE/MAX Compass, formerly RE/MAX WHP) over 7 years ago

Greg - I would probably switch it back because it doesn't meet code.  On the other hand, if the new home buyer wants it to stay, I'll leave it.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Well I wondered about the lengts of those runs. It seems excepionally long. Good planning should hve a HWT placed in better proximity.

Most of what I see is between 10 and 20 feet.


Posted by Robert Butler, Montreal Home Inspector | Aspect Inspection (Aspect Inspection) over 7 years ago