# How come toilets in office buildings don't need a tank? **URL:** \ **Category:** Factual Questions\ **Created:** [December 10, 2000, 1:32am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836 "2000-12-10T01:32:37Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Sangria](https://avatars.discourse-cdn.com/v4/letter/s/87869e/32.png) [@Sangria](https://boards.straightdope.com/u/Sangria)\ **Post date:** [December 10, 2000, 1:32am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/1 "2000-12-10T01:32:37Z")
If I wanted to install a tankless toilet at home, would it work? Or is there some hidden tank like on the roof or something? Do you need super water pressure? ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [December 10, 2000, 1:40am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/2 "2000-12-10T01:40:15Z")
You need a BIG supply pipe, IIRC (and I’m no plummer) most have a 2" feed - I think you can get away with a 1" feed though for some models ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [December 10, 2000, 1:52am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/3 "2000-12-10T01:52:37Z")
I was just looking at the thread 'What are the steps to change C: and D: so system is on D: ? ’ and what dod I see but > [@](#): > > If I wanted to install a tankless toilet at home, would it work? Or is there some hidden tank like on the roof or something? Do you need super water pressure? Well actually I took this quote from this thread, but my point being, I just couldn’t believe I saw this thread there. I thought I’d been had, that this is all a big joke - then I say that you posted there by mistake and burst out laughing. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [December 10, 2000, 1:54am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/4 "2000-12-10T01:54:44Z")
A _plumber_ is better at the type of work you describe, **k2dave**. If you get confused, just remember that the symbol for lead, Pb, is derived from the Latin _plumbium_, because plumbers used the metal in pipes. (I’m done picking nits now.) ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [December 10, 2000, 2:22am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/5 "2000-12-10T02:22:08Z")
thankyu fore corectng meye mistaek ---
**Author:** ![barbitu8](https://avatars.discourse-cdn.com/v4/letter/b/839c29/32.png) [@barbitu8](https://boards.straightdope.com/u/barbitu8)\ **Post date:** [December 10, 2000, 2:58am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/6 "2000-12-10T02:58:36Z")
And I thought plumbing derived its name because all the pipes are laid plumb. Dumb. ---
**Author:** ![LifeWillFall](https://avatars.discourse-cdn.com/v4/letter/l/46a35a/32.png) [@LifeWillFall](https://boards.straightdope.com/u/LifeWillFall)\ **Post date:** [December 10, 2000, 3:01am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/7 "2000-12-10T03:01:53Z")
At my bosses house he has one of those tankless toilets, the only thing strange I noticed is the handle to flush which is just connected to a pipe is higher than in most houses. I didn’t see any extra large pipes in the area ---
**Author:** ![Anachronism](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@Anachronism](https://boards.straightdope.com/u/Anachronism)\ **Post date:** [December 10, 2000, 3:07am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/8 "2000-12-10T03:07:52Z")
To flush a toilet you need a (relativly) large volume of water delivered quickly. A commercial building has the large supply and pressure necessary to do this without a tank. IIRC a flushometer (the valve that flushes a tankless toilet) uses a 1 1/2" supply pipe. Most houses only use a 3/4" supply for the whole house. There is a type of household toilet that uses a pressurized(sp) tank to flush more efficently. I new that 4 years of trade school would come in handy some day :). ---
**Author:** ![nebuli](https://avatars.discourse-cdn.com/v4/letter/n/0ea827/32.png) [@nebuli](https://boards.straightdope.com/u/nebuli)\ **Post date:** [December 10, 2000, 3:12am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/9 "2000-12-10T03:12:23Z")
> [@](#): > > And I thought plumbing derived its name because all the pipes are laid plumb. Dumb Not really so dumb- it is in the same etymological ballpark. Something “Laid plumb” means something aligned as if measured by a plumb line- and a plumb line is simply a string with apiece of lead on one end. ---
**Author:** ![Skelji](https://avatars.discourse-cdn.com/v4/letter/s/b38774/32.png) [@Skelji](https://boards.straightdope.com/u/Skelji)\ **Post date:** [December 10, 2000, 7:45am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/10 "2000-12-10T07:45:28Z")
**Derleth** wins the prize. The name plumber is derived from the Latin word for lead. Water pipes were originally made of lead, which likely helped the fall of the Roman Empire, as everyone became demented from lead poisoning. Later on, when cast iron was used for piping, the joints were sealed with lead. Some old time plumbers will still melt lead to seal hubbed cast iron drainage pipe. ---
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [December 10, 2000, 10:31am UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/11 "2000-12-10T10:31:17Z")
I win? Really? Upon rereading my post, I don’t think I ever explicitly said that plumber came from _plumbium_. As I read it, my post says that Pb comes from _plumbium_. I knew those terms (plumber and _plumbium_) have related origins, and I knew the reason, but I never suspected a causal relationship. Another piece of ignorance eliminated by the members of the SDMB! ---
**Author:** ![Green\_Bean](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/green_bean/32/1760_2.png) [@Green\_Bean](https://boards.straightdope.com/u/Green_Bean)\ **Post date:** [December 10, 2000, 2:56pm UTC](https://boards.straightdope.com/t/how-come-toilets-in-office-buildings-dont-need-a-tank/44836/12 "2000-12-10T14:56:01Z")
> [@](#): > > \*Originally posted by jimshep \* > There is a type of household toilet that uses a pressurized(sp) tank to flush more efficently. We have these, and they work great. They use about the same amount of water as a low-flow toilet, but flush a _lot_ better, if you know what I mean. > [@](#): > > If I wanted to install a tankless toilet at home, would it work? I guess this has been answered, but I did recently read instructions on how to install a home toilet so that it would _look_ like it was tankless. Basically, you enclosed the tank part in the wall, while leaving the bowl part out. I guess this would only work on certain styles of toilets, and I don’t know how you would get to the tank if you needed to service the tank… But apparenly, you can acheive the look of a tankless toilet if you wish.