You may or may not have wondered why the hot water is always on the left side of a faucet. And you may or may not have wondered how long that has been the standard and who came up with it. In case you were wondering…
Why Hot Water is Always on the Left Side of a Faucet
Back in the 19th century, when indoor plumbing was introduced, water was brought into the home by hand pump. At the time, there was only one option that came out of the hand pump: cold water. Since most people were — and still are — right-handed, the pump was placed on the right side of the sink.
Instant hot water was introduced many years later. With the cold water pump already occupying the right side of the sink or tub, the logical place to put the hot water faucet was on the left side of the cold water faucet. There you have it!
As for who came up with it, there’s always Wikipedia.
Why Toilet Flush Handles are Always (or Usually) on the Left
I mentioned above that since a majority of people are right-handed, early hand pumps were on the right side of a sink or tub. Meanwhile, toilet flush handles are always on the left. What’s the deal?
Early indoor toilets had pull chains connected to overhead water tanks. Again, since most people were right handed, the pull chain hung down on the right side… the right side from the perspective of someone sitting “on the throne”. As flush handles evolved into the levers we know them as today, they just happened to stay on that side; the left side from the perspective of someone looking at the toilet.