I've seen in shows where a character will be taking a shower, another character will use the sink, and the showering character will get hit with hot or cold water. I've never experienced this. Is the joke outdated, or do i just live with considerate people?

[u/BeepBoopBapBam]

[u/LordNoFat]

A lot of modern plumbing prevents that from happening. It was more common with older plumbing.

[u/Fun_Tune5669 → u/LordNoFat]

Can attest to this, my house is 100 years older than me, and despite the upgrade that was done here by previous owner like 20 years ago, if my gf is taking a shower and I start doing dishes I'm hearing the alphabet of Ukrainian/Russian cuss words from the bathroom.

[u/sabhall12 → u/Fun_Tune5669]

This is the same in my Edwardian house, whenever someone starts washing the dishes I will jump out of the water stream as fast as possible 

[u/Kevan-banned → u/LordNoFat]

At least in my house, my shower makes its own heat. As a child when it came from the boiler someone running a tap was rage inducing.

And then there was the boiler running out of water when my sister took a bath.

[u/Fun_Tune5669 → u/Kevan-banned]

As a kid I remember this wasn't an issue. But my childhood homes (both of them) were kind of big so the pressure shift wasn't that huge when a single tap was turned on. Only became an issue when I started living on my own in, well relatively small houses.

[u/Kevan-banned → u/Fun_Tune5669]

Check out Big Boiler Boy over here.

Jokes.

[u/Fun_Tune5669 → u/Kevan-banned]

We have geothermal water here. No boiler needed. We do however have heat exchangers, but thanks for the chuckles.

[u/Kevan-banned → u/Fun_Tune5669]

So you're winning Frostpunk? Everyone has to flex

[u/Avium → u/LordNoFat]

Newer shower valves balance the hot and cold pressure so the temperature doesn't change anymore. The shower just feels weaker.

It's called a pressure balance valve and they were made mandatory in Canada for all new shower installations as of 1995.

[u/cam-san → u/LordNoFat]

Our apartment complex was built in the mid 2000s and I still get burned from the water (I shower very hot) when someone flushes the toilet. I hate it and can't wait to live alone.

[u/Dapper-Condition6041]

Typically, flushing the toilet will draw cold water from the shower supply while the tank refills, increasing hot water in the shower.

Most people just don’t realize.

[u/BoredAtWork1976 → u/Dapper-Condition6041]

In the United States at least, it's typically a flushing toilet, and usually either a very old house or an apartment building.

[u/pug_fugly_moe → u/BoredAtWork1976]

My house is from 1978 and does this.

[u/True_Celebration7088]

So this happened when I was a kid, but not since becoming an adult and I have no idea why lmao

[u/LazyAssLeader → u/True_Celebration7088]

Modern fixture prevent scalding by mixing hot and cold water. It's nearly impossible to get all hot water out of a residential fixture.

[u/niboras → u/LazyAssLeader]

This. It is impossible in most places to buy a shower or sink fixture that doesnt mix hot and cold water based on water pressure at the faucet. 

[u/Avium → u/True_Celebration7088]

Because in 1995 the building code changed to make pressure balancing shower valves mandatory...at least here in Canada.

[u/ac54]

Depends on the design of the plumbing. It’s a real thing, especially in older properties.

[u/MaTtHeW111904]

If someone flushed the toilet or turned the sink on I’d get boiled alive in the shower as a kid. And if someone had the sink on hot or was using the washer I’d have freezing arctic shower water. House was made in like the 40s

[u/Ansible90]

Many older houses had smaller water heaters than they do today. They also had shared piping, so one hot water pipe might lead to that bathroom, and then spilt into 3 for shower, toilet and sink. So turning on the sink hot water faucet while shower is on will draw hot water from the shower because they are both being fed from the same pipe.

[u/RadioactiveLily]

Still happens in my house with our older plumbing.

[u/recjus85 → u/RadioactiveLily]

Same

[u/SuchAmphibian26]

Old plumbing trauma.

Flushing the toilet meant fighting for your life back then lol

[u/Nytelock1]

I used to do this to my sister as a kid, she got soo pissed lol. But yes older plumbing had that issue.

[u/LadyAlexTheDeviant]

Yep, it's an issue in our house. Though the bigger issue is hot water capacity. We always check before bathing or showering to make sure no one's running the dishwasher/washing dishes, because otherwise halfway through your shower you'll run out of hot water.

[u/EatYourCheckers]

It really depends on the house and the plumbing.

[u/Dense-Paper5499]

It was very common when I was growing up and also o my applied if they flushed the toilet or used the cold water, it would siphon off some of the cold flow to she shower so the water got hotter. Haven’t had this issue in a long time though living in homes less than 50 years old.

[u/Training-Equal-7647]

Depends on how the whole system is set up, i don't know the specifics, just that this used to happen to me but it stopped after we switched the thermo tank. 

[u/Goobersita]

Our double wide has this problem, we don't run the washing machine or dishwasher when someone is showering.

[u/HappyCamperDancer → u/Goobersita]

This used to be a problem 30-plus years ago, but to this day my husband still hates to take a shower with the dishwasher or washing machine on.

Old habits die hard.

[u/Goobersita → u/HappyCamperDancer]

Our place is exactly like the movies. Instant hot water followed by ice cold water. It's really a lot of screaming for a single shower.

[u/ThinkWishbone2495]

No it's most definitely not. Also flushing the toilet. I believe it has to do with old plumbing and/or old hardware. I'm getting my 4 yr old shower replaced (handyman vs professional) and he asked the same question....but knew the correct answer.

[u/Automatic_Mulberry]

Newer shower control valves are temperature-pressure compensating (TPC) valves specifically to prevent this (this almost certainly depends on where you are, though).

If someone flushed the toilet without one of these valves, it could lower the pressure on the cold side, potentially scalding the person in the shower. TPC valves adjust the hot side pressure to match when this happens, preventing the problem.

I have had it happen to me in the past, but not lately.

[u/Tricky-Awareness-275]

The first time I stayed with my daughter (25) at her apartment, I asked her if I need to let her roommates know that I was taking a shower, to prevent this specifically in case they were gonna wash dishes or something. She could not understand why the hell I would ask that question and did not believe me when I said that's how it used to be..

[u/bowhunterb119]

My last house was like this. I move a lot and it’s never been an issue before but it must have had older plumbing. Using any faucet in the house would affect the shower. If I was taking a hot shower and my spouse used the hot water in the kitchen or other bathroom or the dishwasher was going it would get cold. Took a while before we figured out why the shower temp would fluctuate intermittently a lot of the time.

[u/Due-Cry-3884]

Unscrew the shower head and put a chicken soup cube in it, put it back on.

[u/pepperbeast]

It can definitely happen in older plumbing setups with pressure-reduced hot water.

[u/betelgeuse206265]

Most even reasonably modern showers have thermostatic mixing valves that can compensate for the drop in cold water pressure by dropping hot water pressure at the same time. Then, the temperature stays consistent.

[u/green_meklar]

It depends on the plumbing arrangement in any given building, but yeah, this can totally happen.

[u/TeuthidTheSquid]

Never lived in a house over 50 years old, I guess?

[u/Several-Opposite-746]

When I was a kid living in an older home, flushing a toilet was a great way to get back at a sibling.

[u/Taupe88]

the key is to listen for the flush!!

[u/SilentJoe1986]

When you have 1 hot water tank it can divert the hot water from the tap theyre using so the water gets cold if they are using the hot water, or divert the cold water filling a toilet tank when they flush causing the warer to fet hot for a moment

[u/I_Am_Zeelian]

Very common in older houses.

[u/randomn49er]

Many valves are now pressure balanced. It is code in my area if you don't use a pressure balanced valve you have to install a mixing valve. Basically all this prevents just full hot (scalding)  coming from the faucet. 

[u/xiknowiknowx]

Living in an old three flat in Chicago…i notice when neighbors use the plumbing. My shower gets so hot.

[u/Snoo-32071]

My ex punched a hole in the bathroom wall because I forgot to not use the kitchen sink while he was showering. When it happened to me, I just stepped back from the shower head until the water was warm again.

[u/Md655321]

It depends on your plumbing system but yes it can happen

[u/libra00]

It was pretty common back in the day (source: grew up in the 70s/80s). You'd be in the shower, someone would flush the toilet in the downstairs bathroom, and all the cold water would rush down there leaving only hot water pouring out of the shower. At least in my house it always made a specific sound before it happened so I could duck out of the way for a few seconds.

[u/DjinnOftheBeresaad]

Every house I grew up in had this problem. I'm not super old, but all of the houses were.

[u/Inner-Tackle1917]

These days a lot of (but not all) showers heat water on the fly themselves,  so it won't happen (though you might notice a pressure drop if someone turns on a tap). 

But historically all, and to this day many showers work by receiving hot water from the houses boiler. This means there's a limited supply of hot water for the whole house. So if someone turns on the tap, this can cause a sudden change in the ratio of hot to cold water the shower receives. If they turn on the hot tap, the shower gets colder, if they turn on the cold, it gets hotter. 

[u/-FakeAccount-]

I've lived in 4 different houses that did this. Its typically when the shower is far from the water heater.

[u/zukolivie]

It depends on the house! Newer builds don’t have the same issues.

[u/chubbygrannychaser]

Starting to become dated (at least by US standards). There are temperature/pressure balance valves becoming more common now.

For the rest of us, we get the temperature of the water right by adjusting the balance between hot water and cold water. We use the 1 or 2 faucet/tap controllers to regulate how much hot and how much cold are mixing for our shower.

Someone else using a lot of water suddenly throws off the available pressure and that can drastically change the temperature of the shower water. I'm more familiar with flushing a toilet to create this situation.

It's becoming less frequent as newer hardware gets common.

[u/Maiace124]

I used to have this happen a lot, but now the places I live have updated plumbing so it's not an issue

[u/Leolo_]

Old showers had a knob for hot and another for cold. If the pressure into one knob won't go down, the flow of that type of water goes down. So if someone else starts using hot water, less pressure at the hot knob, less flow through the hot knob, less hot water out of the shower and you end up with a cold shower. Same thing in for cold and hot.

The effect was real but exaggerated for laughs. I lived in an apartment where I had to make sure the next door neighbour wasn't taking a shower before I could flush the toilet.

All new showers have a single knob that you pull and turn to get water. This single knob is called anti-scald and is engineered to compensate for varying pressure in the hot/cold lines.