Is Hot Water Always On The Left?

Perhaps you’re installing a new faucet and come to the step where you hook the water supply lines directly to the faucet.

As you hook up each line to the appropriate side, you begin to wonder why the cold is on the right and the hot is always on the left. Or, maybe we missed the mark, and you’re wondering why your faucet is giving hot water from the right side.

Key Points:

  • Hot water is always supplied from the left side of a sink faucet and cold from the right, per the Universal Plumbing Code.
  • Many sinks with one handle have distinguishing features such as a thin colored band or round cap to indicate hot/cold.
  • If the supply lines to a faucet are crossed, they can easily be switched, which will allow for the right temperature to come out of each side.

Whatever your reasoning might be, we’re here to answer the question: Is hot water on the left? Let’s find out.

A Peek Into History

The reasoning behind the orientation of hot and cold taps dates back a few years. So, let’s take a trip down memory lane. Decades ago, when indoor plumbing was new on the scene and faucets were a novelty, most sinks featured one single pump. This pump supplied cold water to the tap and was regulated by a handle on the right side. The orientation of the handle was designed to accommodate the majority of people who are right-hand dominant.

Skip forward a few years, and you’ll see dual-temperature faucets appear on the scene. Since cold water was already on the right, manufacturers installed the control for hot water in the free space – the left side. This was the logical choice since the right side was already occupied, and the handle needed to be in an easily accessible location.

So, now, we see hot water taps consistently on the right side of the faucet, with the cold handle holding up the right flank. Of course, some faucets only feature one handle, but even then, these faucets feature hot water on the left and cold on the right. Folks control the temperature by turning the tap in either direction since there isn’t a handle for each temperature.

Does The Hot Water Tap Have To Be On The Left Side Of The Facet?

Bathroom Faucet

While hot water seems to always be on the left side of the faucet, is it actually a requirement? The answer is yes – today, the Universal Plumbing Code requires faucets to have hot water correlating with the left side of the fittings.

You could switch the water lines, so the hot water is on the right side. However, since most of us are used to hot water on the left, turning on the right tap and getting hot water would be a surprise. If the water temperature was set high enough on the heater, you could even scald yourself. So, it’s best to stick with the guidelines and keep the hot water on the left.

Faucet Design

You’ll see the hot water faucet and cold water faucet placement reflected in kitchen and bathroom faucets on the market today. Many modern faucets feature identifying features with blue and red markings. For example, there might be a thin colored band around the handle of each faucet that indicates the hot and cold sides.

Or, on a single-handle faucet, there might be a small round cap on the base of the handle. The left half of the cap is red, whereas the right half boasts a blue hue. So, if you tilt the faucet’s handle to the left, you’ll get hot water, but if you tilt it right, you’ll get cold water.

Although many faucets feature some type of temperature identification, not all faucets have these features. Even still, hot water is always on the left, while cold is on the right.

What If The Hot And Cold Sides Are Switched?

Prime-Line MP54260 Hot and Cold Faucet Handles, 1-5/8 inch Height, Clear Acrylic, Delta, 2 Count

Let’s say you installed your first faucet as a DIY project and mixed up the supply lines. Or, perhaps you had a contractor come in and install the faucet, and the temperatures are backward. Either way, the result is hot water from the right side and cold water from the left side.

So, what should you do? If the problem is as simple as crossed supply lines, you can easily correct the issue. Simply switch the supply lines so the cold water correlates with the right and the hot water matches the left.

However, in some cases, the supply lines might be correctly placed, but hot water comes out of the right side too. This is usually the result of too close hot and cold water supply lines. If the supply lines run parallel to each other on their way to the faucet, they can affect the temperature in the opposite line (cold becomes warm, hot becomes warm).

The issue can also stem from other issues, like issues with ventilation ducts or a faulty thermostat. If you suspect one of these to be the culprit, it’s usually best to seek the help of a licensed plumber.

Frequently Asked Questions (FAQs)

How Hot Should My Hot Water Be?

Most experts recommend homeowners set their water heaters to 120 degrees Fahrenheit. This temperature is high enough to offer plenty of heat for washing dishes, taking showers, and running the dishwasher, but not so hot that it will scald you.

However, 140 degrees Fahrenheit is widely considered the default setting. Of course, you can choose to set your water heater to the temperature that works best for you, but avoid setting it too hot, as you could scald yourself. On the flip side, avoid setting the thermostat lower than 120 degrees, as it raises the risk of bacteria developing inside the heater (such as legionella).

Leave a Comment