Have you ever wondered why hot water is usually on the left side of a faucet and cold water on the right? Is this a universal rule or just a convention? And what happens if you encounter a faucet that has the opposite arrangement? In this article, I will explore the history, logic, and code behind the placement of hot and cold water taps.
The History of Hot and Cold Water Taps
The origin of the left-hot-right-cold rule dates back to the early days of indoor plumbing when faucets were a novelty and sinks had only one pump for cold water. The pump was controlled by a handle on the right side of the faucet, which was convenient for most people who are right-handed. The handle also indicated the direction of turning the water on and off: clockwise to close and counterclockwise to open.
When dual-temperature faucets became available, the cold water handle remained on the right side, while the hot water handle was installed on the left side. This was a logical choice, as it avoided confusion and made use of the free space. It also created symmetry and balance in the faucet design.
Since then, most faucets have followed this pattern, with hot water on the left and cold water on the right. Even single-handle faucets, which allow you to adjust the temperature by moving the handle sideways, have hot water on the left and cold water on the right. Some faucets have color-coded indicators or labels to help you identify which side is which.
The Logic of Hot and Cold Water Taps
Apart from historical reasons, there are also some logical reasons why hot water is on the left and cold water is on the right. One reason is that it follows the natural order of things: hot things rise and cold things sink. Therefore, it makes sense to have hot water on top (left) and cold water on bottom (right) when looking at a faucet.
Another reason is that it matches the way we perceive temperature: we associate left with warm and right with cool. This is because our brains process information from our left eye faster than from our right eye, which creates a slight bias towards the left side. Therefore, having hot water on the left and cold water on the right feels more intuitive and comfortable.
A third reason is that it prevents accidental scalding or freezing. If you are used to having hot water on the left and cold water on the right, you will instinctively reach for the correct handle when you want to wash your hands or take a shower. However, if you encounter a faucet that has the opposite arrangement, you might get burned by hot water or chilled by cold water if you are not careful. This can be especially dangerous for children or elderly people who have sensitive skin or slower reaction times.
The Code of Hot and Cold Water Taps
While hot water on the left and cold water on the right may seem like a common sense rule, it is also a legal requirement in some places. According to the Universal Plumbing Code (UPC), which is adopted by many states and countries, faucets must have hot water correlating with the left side of the fittings and cold water correlating with the right side of the fittings. This means that if a faucet is on the side of a bathtub or a sink, the hot water valve must be on the left when viewed from inside the tub or sink, but would be on the right if approached from outside the tub or sink.
The UPC also specifies that faucets must have temperature-limiting devices to prevent scalding or freezing injuries. These devices can be either pressure-balancing valves or thermostatic mixing valves, which regulate the water temperature and flow according to the changes in water pressure or temperature in the supply lines. The UPC also requires that faucets have anti-siphon devices to prevent backflow of contaminated water into the potable water supply.
The UPC is not the only plumbing code in existence, however. Some states and countries may follow different codes, such as the International Plumbing Code (IPC) or the National Plumbing Code of Canada (NPC). These codes may have slightly different rules or exceptions regarding the placement of hot and cold water taps. Therefore, it is important to check with your local authorities before installing or replacing a faucet.
Is Hot Water Always On The Left? Yes, hot water is always on the left, and cold water is always on the right, according to the history, logic, and code of plumbing. This rule helps us avoid confusion, discomfort, and injury when using faucets. However, there may be some variations or exceptions depending on the type of faucet, the location of the faucet, and the plumbing code in your area. Therefore, it is always wise to check the indicators or labels on the faucet before turning it on and to adjust the temperature carefully to suit your preference.