Is Blue Always Cold And Red Always Hot On A Water Faucet?

Which side is hot and cold on a faucet? Is the right side (blue dot) COLD and left side (red dot) HOT? I recently installed a new water faucet. I connected the water lines under the sink so the Red color dot on the left side is Hot water and the Blue color dot on the right side is Cold water. I realize this is the universal standard. However, I was at a restaurant washing my hands and the opposite was happening. Did they install it wrong or is every water faucet different? I was told by a plumber that all water faucets should be hot when you move the handle or the knob on the left and all water faucets should be cold when you move the handle or the knob on the right. Can you explain?

Which side is hot and cold on a faucetWhich side is hot and cold on a faucet?

FACING THE FAUCET (standing in front of the water faucet)…
RED = HOT WATER = LEFT side of faucet
BLUE = COLD WATER = RIGHT side of faucet

The RED color coding on a faucet is always HOT water.
The BLUE color coding on a faucet is always COLD water.

Turn the faucet knob or handle to the LEFT for HOT water.
Turn the faucet knob or handle to the RIGHT for COLD water.

Water Faucet - Red Left - Blue RightWater Faucet – Red Left – Blue Right

RED is known universally as HOT. (RED color relates to FIRE = HEAT)
BLUE is known universally as COLD. (BLUE color relates to ICE = COLD)

HOT WATER on any faucet should always be from the LEFT side and RED color.
COLD WATER on any faucet should always be from the RIGHT side and BLUE color.
This applies to all single lever or split faucet types.

If there is no color coding on the faucet, just remember that COLD is right and HOT is left.
All water faucets should be this way regardless of being a kitchen faucet or a bathroom faucet.

Kitchen Faucets - left is hot right is coldKitchen Single Handle Faucet – left is hot right is cold

Single handle faucets

On a single handle faucet the way to turn the handle for HOT water is to the LEFT.
On a single handle faucet the way to turn the handle for COLD water is to the RIGHT.

Kitchen Single Handle Faucet - Back is HOT - Forward is COLDKitchen Single Handle Faucet – Back is HOT – Forward is COLD

On newer “forward and back” water faucets handles, move the handle FORWARD for COLD water.
On newer “forward and back” water faucets handles, move the handle BACK for HOT water.

Kitchen and Bathroom FaucetsKitchen and Bathroom Faucets

Which side is hot water under the sink?

Hot tap on left or right? The LEFT side should always be HOT water. When connecting the plumbing under your sink, the left side water line should be connected to HOT and the right side water line should be connected to COLD.
Left side to RED. Right side to BLUE.

Water lines on faucet reversed/opposite?

If the plumbing was connected incorrectly, then the COLD water can come out the RED side and the HOT water can come out the BLUE side. If a plumber reverses this, you can be scalded when washing your hands. A plumber can make an error and connect the water lines opposite of how it should be done. If you hire a plumber and they plumb it incorrectly, have them redo it as this is incorrect.

Why is hot water on the left and cold water on the right?

During the 19th century indoor plumbing was newly introduced. In those early days, water entered a house by using a hand pump. The only option back then was COLD WATER. Since most people are right handed, the pump was always put on the right side of the sink. Years later when hot water was newly introduced, the cold water hand pump was already taking up space on the right side of the sink. The hot water was placed on the left side as the cold water was already in place on the right. This is why HOT is on the left and COLD is on the right.

Have questions about installing a kitchen or bathroom faucet with the hot and cold on the correct sides? Please leave a comment below and we will have a professional plumber answer your questions.

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