Welcome to brain Stuff production of iHeart Radio. Hey brain Stuff, Lorn vocal Bomb here with a classic episode from our erstwhile host, Christian Sager. This one is one of those everyday science questions that's easy to answer, but also easy to prevent from happening in the first place. Why does the shower get hot when someone in the house flushes
the toilet? Hey brain Stuff, Christian Sagar here, Have you ever been taking a shower, you know, gently scrubbing your body, maybe singing Boston's more than a feeling, when all of a sudden, the water becomes scalding hot, potentially burning your special downstairs area. I'm here to tell you that it's not just you. But before I teach you how to fix your plumbing so your shower no longer scorches your flesh, please allow me to first explain how the modern commode works.
A common configuration of pipes in homes is what is called a trunk and brand inch system. It's like a tree with one large pipe, you know, the trunk that has several smaller pipes branching off to things like your sink, your laundry machine, your shower, or your toilet. If one of these pipe trees, branches needs water. Like for instance, when you flush your toilet, there's less water available for
the other branches on the tree. There are around three gallons of water in that tank on the back of your toilet, so when you pull the handle, it flushes all that water to send whatever you've disposed of down the sewer pipe. The tanks subsequently refills, taking water away from the other branches. And here's the important part. Your
toilet only uses cold water. So the reason your shower gets hot is because the flush toilet takes away the cold water that was available in the system to mix together with the hot water coming out of your shower head. And if you're like Goldilocks, you probably like your shower not too hot and cold. But without cold water in the mix, all that is left is nuclear hot lava that will melt your epidermis off. And it's not just
your toilet that can contribute to this problem. Any appliance using cold water can steal it from the shower washing machines, sprinklers, even be days. There are several ways to fix this water temperature problem, and I'm going to present you with a few. The simplest method is to adjust the valve under the toilet's tank. Most of the time these can
be tightened, so the toilet takes longer to fill. Unless you're the kind of person who is constantly discharging bodily waste and you know that's probably something you need to have looked at, you probably don't need the tank to be primed immediately. This will take less cold water away from the shower. A similar simple solution is to place an object like a brick or I don't know, a human skull inside the tank so it doesn't use three
gallons every time you flush. There are more complex plumbing fixes available as well, increasing your trunk's pipe diameter, installing a new mixing valve, or renovating the whole system, but all of those are going to cost you cash money, and let's face it, if you wanted to spend that, you wouldn't be listening to a podcast for home repair answers. So bing bang boom, there's how your toilet works, why flushing it makes the shower hot, and hey, a few
ways you can fix it. Today's episode was written by Christian and produced by Tyler Plain For more on this and lots of other topics. Because it, how stuff works dot com. Brain Stuff is production of iHeart Radio for more podcasts for my heart Radio because at the heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.