Updated: May 25, 2021 by Lonnie Thomas

Which Way is Hot On a Single Handle Faucet?

Have you ever try to use someone else shower, and you couldn’t figure it out? Don’t feel too bad; this happens to everybody, for good reason. The hot and cold knob dilemma is sort of a gray area in the world of plumbing, and in many cases, there doesn’t seem to be a consensus among inspectors, contractors, or plumbers.

For most faucets – hot is left, and cold is right. It’s been the industry standard for over 100 years. Manufacturers like Delta, Kohler, and Moen make single lever faucets that all follow this convention. But what about the type of faucet where the handle only moves up or down?

On kitchen faucets like the Moen Align Pulldown, where the handle is mounted vertically on the side, it’s the same. Left is hot, and cold is right. In other words, counterclockwise (towards you) is hot, and clockwise (away from you) is cold.

But why?

Supposedly it’s for safety reasons, but many people question whether it’s actually safer. The idea is since most people are right-handed, they will reach for the cold handle first, and it’s better to be shocked by cold water than scalded by hot water. I doubt many people scald themselves reaching for the wrong handle.

And if you are left-handed, this may seem like just another unfair slap in the face by the right-handed majority. By that logic, all door handles should be on the right. And why are toilet flush handles on the left? It doesn’t make a whole lot of sense, but fortunately, it’s easy to switch hot and cold, and it only takes a couple of minutes.

How to Switch Hot and Cold Water Lines

How To Switch Hot And Cold Water Lines

One of the easiest ways to switch the hot and cold handles is to switch the water lines. There are two supply lines located under your sink, one for hot and one for cold. All you will be doing is turning a wrench.

Look underneath your sink and locate the cold and hot water shutoff valves. They are two oval-shaped chrome knobs. Each one is attached to a metal water line that runs back up to the faucet.

To shut off the water, turn the knob counterclockwise. After you shut off the water supply, turn on the faucets to make sure the water is off.

Next, you can switch the water supply lines. Use a wrench to unscrew the nut holding the supply line to the pipe by turning it counterclockwise. Reattach the supply lines in the opposite order and tighten them. Make sure you are screwing them on straight, or else it will leak.

Now turn on the shutoff valves to test for leaks. If there is a leak, shut it off right away, remove the nut and retighten it. Test it again.

If your handles have indicators on them (i.e., cold is blue, red is hot), you will want to switch those if you can.

How to Make a Hot Water Adjustment to Find the Perfect Temperature

Another common issue with single-handled faucets is with the temperature. If the water is coming out too hot or too cold, you may need a hot water adjustment. If you want to adjust the temperature, you can change the ratio of hot and cold water (the mixture). All you need is a screwdriver.

Adjust Water Mixture

First, use a screwdriver to remove the handle. How it’s put together depends on the make and model of your faucet. Typically you will either pry off the small plastic cover over the screw, or there will be a screw somewhere under the handle.

Next, you can adjust the mixture. Your faucet will have one or more adjustment screws underneath the handle. Some faucets have a dial.

If your faucet has a screw, turn it counterclockwise to increase the amount of hot water in the mixture and clockwise to increase the amount of cold water.

If your faucet has a dial or a nub, you can use your hand or a pair of pliers to move it. Similarly, turn the dial counterclockwise will increase the amount of hot water in the mixture and clockwise to increase the amount of cold water.