We have a bidet attachment on the toilet so I use next to no toilet paper (2-3 sheets) and it occasionally gets clogged to the point of requiring a plunger. On the Toto, no bidet, but I’ve only clogged it once and a second flush was all it took. Sorry if TMI.
To the OP, when I replaced a toilet a couple years ago, I asked the plumber the question about why flushing effectiveness lessens over time. He explained that toilets do in fact “wear out”. The internal surfaces become worn from use of cleansing agents and even contaminants in the water. As the surfaces wear out, they become rougher, and hence less able to move things along.
Data point of one, but it came from a presumably reliable source.
I replaced a toilet that had been in place for at least 35 years. The new one, a sleek Toto model coupled with a pretty high-end Toto bidet seat, has been a dream to use and flush. No clogs. Not once. I miss that thing when I travel.
Altogether, it cost a lot less than the Numi, which to me looks like an abbreviated recycling container. Sorry, @Jackmannii! I do hope you enjoy it when you have it! For that price, it could become your new best friend!
The Numi has been discontinued. If you really want one let me know. I have a few contacts and might be able to source one.
A bit of a summary of what’s already been said, but my understanding of what makes modern low-flow toilets work so much better are as follows:
- Actual engineering, i.e. fluid dynamics, 3D CAD modeling, etc. rather than just “doing what worked before.”
- The glazed trap definitely helps move things along.
- Jet assist, which some old toilets had too. This is the water inlet at the very bottom front that shoots the water into the drain at the back. It helps prime the siphon, and it helps to force out the waste in the direction it’s supposed to go.
- Larger tank/bowl connections which dump water into the bowl more quickly helps it do more work with less.
- Short-action flappers. Old toiles would almost completely drain the tank on one flush, but most low-flow toilets still have big tanks. They only let out maybe 1/3 or 1/2 of it on one flush due to a different kind of flapper design. That extra volume of water creates more pressure on the water exiting the tank to the bowl, improving performance.
Some disadvantages, also already mentioned, is that with less total water, and more being injected straight into the drain by the jet assist, there’s not a whole lot of water left to wash/scour the bowl, so they may need more cleaning. Some people also just like there to be more standing water. That can kind of be mitigated by adjusting the bowl design so you get more surface area without needing as much volume (basically a shallower wider pool of water rather than a small but deep pool).
Personal anecdote, I have a 1984 Mansfield toilet in my apartment, and it’s total garbage. Clogs if you look at it wrong even though it uses 3.5 gallons (older toilets than that could use 7 gallons or more per flush). Even when it doesn’t clog, the inlets around the rim are so sharply angled, and the water swirls so much, that even it doesn’t always remove all waste (no jet assist either). Basically the siphon breaks before all the water has reached the bottom due to the strong whirlpool, so some waste doesn’t even reach the bottom before the flush is over. Whether this is bad design, bad manufacturing (those holes were/are punched by hand with just a rod and a jig, so the angle isn’t necessarily consistent), or buildup of calcium deposits over time changing the angle. Not all high-flow toilets are great.
As to US versus European toilets, there are some functional differences that can impact perceived performance. US toilets are almost all siphon toilets, with the snaking trap and the characteristic gurgle when the siphon breaks. Because the trap is longer, and the siphon requires a certain volume of water per diameter of drain pipe, that’s more often a restriction that can cause clogging. Washdown toilets like you find in Europe (Australia too?) just have a short barrier between the bowl and the drain and use the force of water to push the waste out, with no need for a siphon. That has an advantage for being more clog resistant, but there’s also usually very little standing water, like only a few cups in the drain. That means more odor while doing your business, and more need for the scrub brush. There’s also an argument to be made that making the toilet the “weak link” as far as clogging means you’re less likely to block up your pipes farther down the line where they’re harder to get to.
We chose not to get those. And on three if the four toilets in the house, that’s fine. But the one in the guest bedroom must have been designed for soft close or something. The damn thing won’t stay up, the seat comes crashing down.
You can open or close the lid fine. But not the seat. It’s just not stable in the “up” position. This is a nuisance right now, because we are fostering kittens, and I’d like to raise the seat to scoop poop into the pot.
Grandma’s house had an old toilet in the basement that had the tank located near the ceiling, with a hefty (2" - 3") pipe connecting to the bowl. You used a pull chain to flush it.
Don’t know if it was the amount of water it used (surely not low-flow!), or the extra gravity push from the high tank, but that toilet was at least 50 years old, and worked great every time.
I imagine that cat poop is the same as human poop to the plumbing, but if you are flushing kitty litter down there with it, it will wreak havoc.
This is like my 10th foster litter. I’m not worried about the plumbing below the toilet. But it’s a new toilet, and it’s a nuisance that the seat won’t stay up.
I imagine it’s a nuisance for guests who might like to stand to use the toilet, too.
An excellent toilet can be foiled by outright bad or near the limit plumbing. What goes on between the base of the toilet and the stack.
I removed and replaced all the wild mix of cast iron, plastic, copper plumbing in two houses, plus one other bathroom in a third house. In every case the new systems drained better. Sometimes dramatically so. Most newer houses should have decent systems. But a lot of older and old randomly renovated ones can have nightmares in plumbing and electrical, that replacing the surface items just won’t solve.