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Answer The waste line from the downstairs toilet is not vented (or not vented properly, or the vent is plugged up). Flushing the upstairs toilet creates a vacuum in the main line which sucks the water out of the one downstairs. Answer your waste lines for both toilets may be on the same branch off the sewer main. Either you have a stoppage in the branch line or you have a stoppage in the main line. (If it's the main line your downstairs toilet would have to be the lowest fixture, ie If you have a floor drain downstairs and it's a stoppage in your main line it would backup through the floor drain. If there is no floor drain the toilet downstairs is probably your lowest fixture.) Your best bet is to snake out the system through the toilet downstairs.

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โˆ™ 2015-02-06 10:47:18
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Q: Why would the water and everything come out of the downstairs toilet when you flush the upstairs toilet?
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Related Questions

Why would toilet upstairs cause toilet downstairs to flush?

The downstairs toilet is not properly vented and the flow from the one upstairs creates a vacuum in the waste line.

Why when you flush one toilet upstairs does the toilet downstairs make water noises?

Because they are, in effect, connected

What would cause an upstairs toilet to flush when you run a tap downstairs?

Back syphonage or a defective flapper / tank bulb

Can you flush the upstairs toilet when you have the downstairs toilet off and capped off?

If your plumbing system is properly installed there should not be any problem. If it isn't installed properly, you would already have water from sinks and bathtubs backing up out of the downstairs toilet.

Hwy when you flush your upstairs toilet does your downstairs shower drain erupt sewage?

The drain from the toilet to the main drain is plugged and the branch to the shower is not. If the main floor toilet flushes, it is between the two toilets and not between the house and the sewer.

Why does your basement toilet back up when you flush upstairs?

The main line going out is getting clogged or has collapsed.

What happens when you flush the toilet in a blackout?

you flush the toilet

What is a double flush toilet?

One in which everything doesnt make it down the first flush so you give it another go.

What should you do if you have not flushed an upstairs toilet for about five months and the bowl is now completely dry?

Yes you can flush it. It's possible for a toilet trap to go dry after that much time. When you flush just make sure you check to see if the bowl is leaking.

Can you flush shorts down a toilet?

It depends on how big the shorts are, but either way the shorts would get stuck in the toilet and clog everything.

What would cause a large air bubble in a downstairs toilet directly below an flushed upstairs toilet and what is the best fix?

When the up stairs toilet is flushing.The toilet tank releases water to flush down the toilet bowl.While the toilet tank draining out water to flush and before refilling .The air that gets trapped before the floater shuts to refill the tank.That may be the air that causes the pressure to blow alarge bubble out from downstairs toilet. Bubbles in the toilet that you flush might mean that you need your sewer line cleaned. A significant amount of water leaves the upstairs toilet in a relatively short amount of time. If the drain pipe to which it is attached is "small" (three inch rather than four inch) or partially plugged or insufficiently graded, a small air pocket can form immediately in front of the oncoming waste and water. It will follow the path of least resistence. If it requires more pressure to continue down the line than is required to escape through the branch line to the downstairs toilet, the downstairs toilet will "burp", especially if it is not vented seperataly from the main vent, or if its' vent is plugged or partially plugged. I agree, first try cleaning the line. Do it right, with a proper size blade or spud running well out of the house. If that doesnt solve the problem, investigate the vent. Answer 1 is TOTALLY incorrect. It is addressing the "flush valve," [also refered to as a "flapper"], suggesting the possibility of air "ingested" before it recloses [to allow refill of the tank] "may" be the source of the air bubbling out the downstairs toilet. That air simply goes into the upstairs toilet bowl, not down the drain/waste pipe. Therefore, it cannot be related to the bubbling downstairs. Answer 2 is also totally incorrect due to the fact it is refering to bubbling in the toilet which is flushed [the "upstairs" toilet], which is not related to the bubbling in the downstairs toilet described in the question. I agree with the explanation in Answer 3, with the exception that I would visually check [with a powerfull flashlight] the vent stack for the downstairs toilet [or at least the viewable section of a shared stack], understanding of course, that unless the vent stack is a perfect straight shot, a visual check would be limited to only the straight run section. In our area, over 95% of houses are single story, and checking the drain/waste vents from the roof is no big deal. On two or three story houses, it may be better to try cleaning the line(s), assuming that adequate cleanouts are available. Many of our older houses were not required to have cleanouts, and we have break into walls or dig earth to install them. Otherwise, IF the client WILL NOT go for the cost of add-on cleanouts, we HAVE to work through the roof vent stack opening. This is not uncommon for our area.

When did John Harringtoninvent the first flush toilet?

He Invented The First Flush Toilet In 1568.

What happens if you don't flush a toilet?

Well, it depends how many times you don't flush a toilet. If you don't flush it one time, nothing happens. But if you don't flush it for a month or something, and then you finally flush it, it may get clogged with toilet paper.

Will Emily osment go to college to learn how to flush a toilet ow to flush a toilet?


Does a toilet flush counter clockwise in usa?

Yes, a toilet does flush counter clockwise in the USA.

What will happen if you flush your pet rabbit down the toilet?

Don't Flush any kind of animals. You can only flush toilet tissues.

What is the cost to flush toilet?

$1.34 per flush

How do you flush your transmission fluid?

Drain it into a toilet and flush it

How much water does a low flush toilet save a month?

If the toilet works each time on one flush, they use roughly half the water of a standard toilet. You would then use half as much a month on the toilet. They do not always flush completely on the first flush and the toilet is only a part of the water bill.

Why do you flush your toilet?

To eliminate urinary and fecal waste to the sewage. A toilet that doesn't flush is basically a bucket.

Can underwear go down toilet?

You will probably clog your toilet or pipes if you flush anything but toilet paper. I would not recommend trying to flush underwear down the toilet.

What toilet tissue can you easily flush down the toilet?

All toilet tissue is supposed to flush easily in reasonable quantities, NOT in huge clumps

Why would bubbles come from the tank where the flapper is when you flush the toilet?

because there is a Dukie stuck in the bottom of the toilet so you have to take out your toilet and flush the system.

How do you get a snake out of the toilet?

flush it

When did he make the flush toilet?

The invention of the flush toilet dates to the 1590's and is credited to Sir John Harington.