Hot water circulation pump

One of the things that has bugged me with our Solitude 374TH is that the bathroom vanity is so far from the hot water tank. We boondock a lot and don't like to waste water. Having to run the water for 20 to 30 seconds to get hot water to the faucet drives me nuts.

Today's project was to install a small 12 volt water circulation pump under the vanity so we don't send that water down the drain.
The pump I chose was this one sourced through Amazon.

As there is no pressure difference between the hot and cold lines, the pump can circulate the water easily. I installed a simple on/off switch to the side of the vanity so we can turn it on only when needed.

After using this for a bit I found that the cold water was backflowing through the pump when it isn't running. The solution is to add a check valve on the input or output side of the pump to prevent the backflow.

In the photo above you can see the check valve on the input (hot) side of the pump. 

I have found I need to run the pump for about 30 seconds to get the hot water all the way back to the bathroom vanity.