Why are shower drains 2", What gives?

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Mad Plumber

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Why do showers have to be drained with 2 inch, but tubs can be 1 1/2 inch.I've been told,
its because of more constant flow to shower,well i take a shower in my tub everyday! not only that
when the kids get out of the tub ,they sometimes wash quite the glob of sludge down that 1 1/2 inch drain
where the guest house(with shower only) doesn't get all the mud and squished grime that
comes with small children or in many cases pets! what gives

I've got problems with understanding the madness also. A lot of things that in my opinion should be a standard size aren't I sometimes think it's to make us have to buy different size wrenches etc. or just to drive us crazy.

What gives! Why aren't all tubs required to be two inch? How come they're only 1-1/2"? Have you ever had to snake a measly, tiny, smallish little tub drain before. Man!! Don't even think about it! And when you drain a tub when you're done with your bath. I can hear it draining in the next room forever. I'd like a faucet that fills the tub in two minutes, so that the tub is ready by the time I'm undressed. I can't stand waiting. And when I want to drain the tub, Drain it man! When I turn on the jets, I want the water to stay hot. Hot I said! I want that extra little in-line water heater to keep the water hot. Hot, hot I said, not the creepy lukewarm stuff you wind up bathing in. And when I get out the tub, I want a mat to step on. Not that damned cold marble floor that I slip and fall on! Dang! that hurts! When I dry off, I want that towel to be hanging on a oil filled heated towel bar. I want that towel hot too. Damn hot!
Arrghh! I'm such a Mad Plumber!

the reason showers require a 2" by code drain is so that the shower will not over-flow the basin. The tub has an overflow built into the bowl.
Jim Bob

Oh..............thars a reasonx? Okay.
Mad Plumber

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Master Plumber
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Cave Creek, Arizona
You can hold a lot more "excess water" in a tub, than in a shower basin. BUT, the latest IAPMO forum approved a 1 1/2" shower drain when the shower REPLACES a bathtub, but not for new installations. IF you are taking such a long shower that the tub water reaches the overflow opening, you are wasting a lot of water, AND do NOT expect the overflow opening to PREVENT the tub from overflowing on to the floor if you continue with your shower.
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