How Does an Under Sink Hot Water Recirculating Pump Work? Under Sink Installation Guide

How Does an Under Sink Hot Water Recirculating Pump Work? Under Sink Installation Guide

As plumbing techniques and technology have continued to evolve, hot water recirculating pumps have evolved with it. Within the last ten years or so, recirculating pumps have been developed that can give you hot water the second you open your taps. One of the most common types of recirculating pump setups is to have one installed under your sink. 

An under sink hot water recirculating pump works very similarly to a standard recirculating pump. Rather than having the pump installed above the water heater, however, the recirculating pump is installed below the desired sink. While this provides instant hot water to everything between the sink and the water heater, any plumbing fixtures downstream from the pump will have to wait for hot water. 

In this article, we’ll look at how to install this type of hot water recirculating pump as well as if it’s the best option for you. If so, we’ll also discuss some of the top recirculating pumps on the market. 

How do you install a hot water recirculating pump under the sink?

Installing a hot water recirculating pump under your sink has basically the same installation procedures that it would have above a water heater. The only real difference is the location. Let’s go over the step-by-step process of how to install a recirculating pump under any sink in your home. 

Shut the Water Off 

The first thing you’ll want to do is shut off the main water supply and drain any existing water in the lines. You’ll have to cut into your water lines in order to install the recirculating pump, which will result in a wet mess if there’s water in the lines. 

Cut Off the Hot and Cold Shut-Off Valves 

With the water turned off and the lines drained, it’s time to cut off the existing hot and cold shut-off valves in the waterline. You’ll want to cut your pipe on either side of the valve as close to the valve as possible. Make sure that you have enough pipe on the supply side of the valve as well as on the side between the valve and the faucet connection at the sink. 

If you have copper plumbing pipes, a handsaw or pipe cutter is the best tool to use. Make sure to cut carefully so that you don’t create burrs, and use sandpaper to smooth out the edges of the copper. If you have pex pipe, a simple plastic pipe cutter will get the job done. 

Make the Plumbing Connections 

There are several plumbing connections that you’ll have to make, but none of them involve soldering if you purchase the correct pump. Your pump should come with all the necessary connections as well as the pump itself. Connect the water supply line on either side of the recirculating pump. Next, connect the pipes that go from the lavatory to the pump. 

Make sure that each of these connections is secure and tight, as they will involve both compression fittings as well as press-on plumbing connections. 

Secure the Pump in a Safe Location 

With all of your plumbing pipes in place, you’ll want to make sure to fasten the pump securely somewhere within the sink cabinet or cavity. Depending on how your plumbing pipes are running, you can fasten the pump to the base of the cabinet or against the back or sidewalls. Your pump should have a bracket attached to it that you can screw securely into place. 

Install the Power Switch 

Because nobody wants to manually turn their recirculating pumps on by opening the cabinet, bending over, moving things out of the way, and searching for an ON switch, most pumps have a power switch installed separately. The best spot for the power switch is on the outside of the cabinet, where it’s easy to access, but not so much that you accidentally bump into and turn your pump on and off. 

The switch looks similar to a doorbell or a light switch, and there will be a small wire that runs from the switch to the pump. 

Plug the Pump in 

The final step with the pump itself is to plug it in with the attached power cord. If there isn’t any electrical connection nearby, you’ll have to run electrical wiring and install an outlet within reach of the cord. 

Perform a Test Run 

With all your electrical and plumbing connections made, it’s time to turn the pump on and perform a practice run. Wait until you hear the pump automatically turn off, then open the hot side of your faucet. You should immediately be greeted with hot water. 

Best under recirculating sink pump

Because of how innovative and desirable under-sink recirculating pumps are, several excellent options are available. They’re quickly becoming the pump of choice for those who don’t want a full-home system. 

Click here for in depth article on best under sink recirculating pumps.

Taco under sink recirculating pump

One of the top under sink recirculating pumps on the market is made by Taco. Taco plumbing products are some of the best in the business, and their recirculating pumps are no different. These pumps provide instant hot water to whatever sink you install beneath and all other sinks between the sink and water heater. It’s small, silent, easy to install, and comes with all the necessary components and connectors. 

Grundfos under sink recirculating pump

Grundfos is another company that makes a top-of-the-line recirculating pump. Much like the Taco pump, Grundfos pumps come with all the necessary components. They’re equally as small, quiet, and easy to install, and they are one of the best recirculating pumps on the market. If the Grundfos pump has any downfalls, it’s that the water coming out of your taps might be too hot! 

Grundfos Under Sink Recirculating Pump
526 Reviews
Grundfos Under Sink Recirculating Pump
  • Sturdy cast iron housing
  • Flow range: 0- 15.5 US gpm, head range from 1 to 15-feet
  • 2 pole, single phase, 115-volt motors
  • Two 3/4-Inch bolt holes (flanges not included).Maintenance-free, low energy...
  • Max. power input:85 W


How much does it cost to install an under sink recirculating pump?

Installing an under sink recirculating pump costs around $1,000. The pump itself will cost between $500 and $800, and the labor to install it will make up the difference. 

How can I make my kitchen sink water heat faster?

The best way to make your kitchen sink water heat up faster is to install an under sink recirculation pump. 

Final Thoughts

If you can turn your kitchen or bathroom sink on and count to 30 before hot water is finally present, you have a big problem on your hands. Waiting for hot water is inconvenient and inefficient because you’re paying for every drop of unused water that goes down the drain. While the pump and installation cost of a recirculating pump might seem high at first, they will save you time and money down the road and make your life much easier. 

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