Niagara Stealth – Best Low Flow Toilet (Powerful & Quiet)

Niagara Stealth Toilet

Best Low-Flow Toilet With Quiet Power-Assisted Flushing

Quiet and pressure-assisted flushing hardly goes hand in hand for a toilet. But the Niagara Stealth toilet seems to have success in taming the loud explosive nature of pressure-assisted flushing. If this caught your attention, you might be lured onto a trend that favors water saving toilets.

A trend that is triggered by the EPA’s strict water conservation rules in 1992, when 1.6 gallons of water is the maximum capacity allowed for a toilet. Since then, toilet manufacturers are relentless in developing toilets that consume the least amount of water. And today, we see 1.28 GPF, and 1.0 GPF toilets are crowding out the 1.6 GPF models.

But how low can they go? That’s the question which, perhaps, this Niagara Stealth toilet holds the answer.

Niagara Stealth Toilet – A Little Background

Niagara Conservation Corporation

The Niagara Stealth has been around since 2009. That’s the time when 1.28 GPF toilets are only beginning to take shape. And there are only a handful of 1.0 GPF crappers around, which consumers perceived the low volume as only good for flushing liquid waste.

But Niagara Conservation believed otherwise and adopted a contrarian disposition. Which is only natural for a company that specializes in water conservation. So development soon began with a simple idea of a toilet that uses the least amount of water to deliver a powerful and quiet flush.

Then in the fall of 2009, when everyone is still doubting the 1.0 GPF crapper, a 0.8 gallons single flush capacity toilet was officially launched.

Aptly named as the Niagara Stealth Toilet, the reception then was a mix of optimism and skepticism. But today, the skeptics have turned believers, and positive reviews almost fill every e-commerce platforms that carry the product.

And right until the time of this review, the Niagara Stealth Toilet is the only 0.8 GPF toilet in the world. With a performance that even put some of the 1.6 and 1.28 GPF toilets to shame.

Logic Defying Technology

If you are fussy about bowl streaking and odor, the first thing you’d probably check is the water spot size in the bowl. Though not generously huge like a KOHLER or an America Standard toilet, this Niagara Stealth has a water surface size of 8’’ x 6’’.

That’s a pretty decent water surface area for a less-than 1.0 GPF toilet. You will agree if you understand how flush volume correlates to the water amount in the bowl.

All gravity flush toilets have the water level in the bowl determine by the weir. The depth of the water will affect the volume and surface size. So if you go by this conventional wisdom, then the actual water surface area of this 0.8 GPF Niagara toilet should be significantly smaller than 8″ x 6″.

But that’s not how this ultra high-efficiency toilet obtains its water surface dimension.

The Niagara Stealth Toilet uses a pressurized trapway to maintain a large water surface area. With the air in the trapway acting like a stopper, water is prevented from flowing over the weir.

Therefore the water level in the bowl can rise above the spillway. That is how a decent water surface area is possible despite the little water volume in the bowl.

And of course, the pressurized trapway is not there just to make a decent water surface. The large surface size is only a ‘side effect’ of the powerful vacuum-assisted flushing system.

Pressurized Trapway

How Does The System Work?

Similar to a conventional pressure-assisted flushing system, the Niagara Stealth toilet has an inner tank or inner chamber within the porcelain tank.

The visual difference is you will see water in the tank of the Niagara Stealth toilet with the inner chamber partially submerge in it. Whereas the typical pressure-assisted toilet has no water in the tank, you will only see the sealed plastic inner tank vessel.

Unlike the regular pressure-assisted flushing, the Niagara Stealth system doesn’t require pressure to force water out of the tank. The 0.8 gallons of water gush into the bowl, just like any gravity-flush toilets, to rinse and flush waste out of the bowl.

But apparently, with this bit of water, it’s not sufficient to rinse the entire bowl surface and flush out waste. In another word, water from the tank is not for filling the trapway to start the siphon.

Instead, it’s the clever use of air to substitute the lost water volume required to start the siphon in the trapway. Since you can’t use the sheer volume of water to create a vacuum in the trapway, the sudden removal of air in the trapway has the same effect.

Here’s the sequence when a flush is initiated with the push of the flush button.

How the Vacuum-Assisted Flush works

  1. Water in the tank and inner chamber flows out into the bowl rapidly through the rim holes and siphon jet.
  2. The pressurized air in the trapway flows back into the chamber via the transfer tube. Therefore, creating a vacuum in the trapway.
  3. Water in the bowl gets suck into the trapway and start the siphon.
  4. At the end of the flush, water starts to fill up the tank and inner chamber.
  5. As water is filling the inner chamber, the air inside is being pushed back into the trapway via the transfer tube.
  6. When the inner chamber is filled, the trapway is once again pressurized. The air pressure in the trapway keeps the water in the bowl above the weir level, maintaining a large water surface in the bowl.

Well Thought Out Features

If you need to prioritize the features of this Niagara Stealth toilet, the flush capacity has got to be the main one. You will appreciate how much water and money you can save with this 0.8 gallons Niagara Stealth toilet.

You can save up to 50% or 37.5% of water usage against the 1.6 GPF and 1.28 GPF crapper respectively. And up to a whopping 77% if you are still using the ancient 3.5 GPF toilet.

That makes this Niagara Stealth the lowest toilet flushing capacity in the world. Perfect for quenching your water saving obsession. And save you some real money from being flushed away.

But that’s not all it has to offer. Here are the rest of the features that make this ultra high-efficient toilet an excellent investment.

1. Large Water Surface Area

Despite having a low water volume, this Niagara Stealth toilet has a reasonably large water surface area of 8″ x 6″. Though can’t compare with those conventional gravity flush toilets, it is effective in containing odor and reducing waste smear on the bowl surface.

Large Water Surface

2. Fully Glazed Surface

The bowl and trapway surface are glazed to enhance flushing efficiency. This feature is not an option for a toilet that has only 0.8 gallons per flush. The glazed surface plays a pivotal role in the flush performance.

3. Maintenance Free (Virtually) Flush Valve

This Nagara Stealth toilet uses the tower or canister type flush valve which has no flapper in the system. This tower valve system is good because unlike the flapper, it offers excellent seal support and does not wafer.

That’s because the valve seal is a hard plastic plate which presses down and equally distributes pressure across the valve opening. Unlike the hinged flapper which is prone to leaks due to wafering and uneven support around the opening.

But the most significant advantage of a tower valve is the full 360° valve opening that allows more water to flow through without any obstruction. Therefore, you get a powerful gush of water down the bowl for better bowl rinsing and flushing waste out of the bowl.

Tower Flush Valve

4. No More Noisy Tank Refill

Whenever you flush the toilet, you would wish the noise can stop immediately. Particularly so when you have guests at the dining table. Or not to wake anyone at 3 am on a school or work day.

But you can’t help it. As you endure through the flushing part to the end, here comes the filling noise. If that irks you to death, here’s the good news.

The fill valve of this Niagara Stealth toilet is always submerged in water. And the filling happens in the water so you will never hear a drop as the tank and inner chamber gets filled.

And as for the flushing, there’s nothing you can do to silence it altogether. But according to some users, the flush is quieter than most gravity-flush toilets. So now, you only have to get past the no-so-loud flush which lasted for about 2 seconds, and you are back to serenity.

Fluidmaster 400A Fill Valve

5. MaP Performance Score

The flushing power is perhaps the most important thing you have in mind. Considering the flush volume of only 0.8 GPF, it is understandable.

You may still have your doubt about the vacuum-assisted flush, but numbers don’t lie. And coming from the trusted MaP test lab, the test result is the best assurance.

This Niagara Stealth toilet has an impressive MaP 800 score.

If you are not familiar with the MaP score, it means this UHET toilet can remove 800 grams of solid waste in one single flush. And according to MaP’s standard, this Niagara toilet falls under the highest flush performance category.

And by the way, 800 grams is a lot of poop there. On average, a person weighing 160 pounds produces just under 1 pound (454 grams) of poop each day.

6. A Real 17-inch Bowl Height Toilet At Last

17-inch bowl height toilets are rare. Most of the comfort height or ADA compliant toilets out there are at most 16-1/2″ in bowl height.

Though you may argue the half an inch won’t make any difference, it is still good to know the Niagara Stealth has this option for you. And for the folks who have been looking for a no-less than 17-inches high-bowl toilet, this is their holy grail.

But this high-bowl feature may not be everyone’s cuppa. Some may just prefer a standard bowl height toilet. In any case, the Niagara Stealth toilet has two more option of 15-1/2″ and 16″ in bowl height to offer. The only thing left to decide is the bowl shape.

Bowl Height Options

7. Optional Dual-Flushing Mode

Just when you are trying to adjust your mindset to a super low 0.8 GPF, there is the half flush of 0.5 GPF on the up and coming Nano™.

This Dual Flush feature will have two inner chambers. But don’t worry, it’s still taking up a one chamber space in the tank. So the tank size is not getting any bigger. It’s a chamber within a chamber to offer you a full or half flush functionality.

When you press the ‘Half’ flush button, only the primary chamber is activated, releasing 0.5 gallons of water into the bowl. And this is for flushing liquid waste. A ‘Full’ flush utilizes both chambers to release a full 0.8 gallons down into the bowl to flush out solid waste.

If you love this Dual Flush Niagara Stealth toilet, hang in there. The Nano™ will be launched in Fall 2018.

Niagara Dual Flush Toilet

8. Huge Footprint

Large FootprintYou know what it’s like when your new toilet has a smaller base that barely covers the ugly footprint of the old crapper. So a bigger-than-the-old base becomes a criterion when shopping for a new toilet.

And just in case you are sold on this Niagara Stealth toilet, this is the last step you should do before clicking on the Buy Button. Grab yourself a measuring tape and measure your existing toilet base. Then compare with the base dimension of this Niagara Stealth, which is a huge 10.25″ x 20.5″.

Except for the dual flush Nano™ and the 10″ rough-in model, this base dimension is the same for all 0.8 GPF Stealth toilets. The footprint of both the Nano™ and the 10″ rough-in model is longer by 2 to 3 inches.

9. Side Handle Or Top Push Button?

Side Handle Or Top Push-Button

This option might seem trivial after all both works the same flushing mechanism. That will be the case if you have clear space around the toilet.

But what if you have shelves above the toilet tank for organizing your toiletries? Or you have the habit of placing stuff on the tank cover, like spare toilet paper rolls. Then a side handle will be more appropriate, as you will have a flat tank cover.

A top flush button will offer the convenience of access from any sides you are standing. But you will need some hand space above the cover if you intend to install the toilet under some shelves.

Front Side HandleSo is it really an issue of what you choose? Maybe only those with a very small bathroom will understand. Therefore, choosing the right flushing handle or push button can save them some frustrations when every inch of space counts of their tiny bathroom.

Of course, the best of both worlds would be a front side handle. Unfortunately, this Niagara Stealth toilet doesn’t offer that for a flush handle.

10. The Vacuum-Assisted Flushing

Last but not least, the vacuum-assisted flushing carries the most weight among all features. It is what makes the 0.8 gallons flush like a 1.6 GPF. Or even better.

Get a feel of how the awesome vacuum-assisted flushing works, watch the video below.


Standard Installation

Except for the skirted (concealed trapway) models, there’s nothing peculiar you should take note during installation. An experienced plumber should breeze through the installation without the manual.

But if you plan to do the installation yourself, please read through the Installation Manual before anything else. In the manual, you will learn what tools are needed and the steps to follow. Pretty intuitive and no special tools are required for the installation.

Besides, the tank has been assembled by the factory. So you don’t have to deal with whatever that’s inside the tank. That saves you precious time on installation.

The skirted models will have limited access, and you should install the seat first (unless you are using special seat bolts). You may also have to attach the supply line and tank before anchoring these toilets to the floor.

And there are two 10″ rough-in models which you can choose between having a side handle or top push-button for flushing. Unfortunately, both models come with round bowl only. But on the flip side, the 27″ length will fit a small bathroom nicely.

One Disadvantage You Should Know

The trapway is designed to trap air (or pressurized) when the inner chamber gets re-fill. So to achieve the pressurization, two spillway or weir creates the water seal in the trapway.

Water Seal

When you experienced a clog in the trapway, due to its shape (with dual weir point), a plunger may not work well. The best way to unclog this Niagara Stealth toilet is by using a plumbing snake or toilet auger.

But even with an auger, you will find it hard to snake past the tight bend near the lower weir. So to get past the sharp turn, you will need to modify the auger slightly to make it more flexible. You can do this by stretching the coil near the drop head.

The stretched or loosen part of the coil then becomes more flexible. With a little push, the drop head will change direction and navigate through the tight bend easily. Only then can you traverse the entire length of the trapway at ease.

Loosen Auger Coil

So this is the main drawback of this Niagara vacuum-assisted flush toilet. The dual weir is necessary to effect a pressurized trapway and not a design flaw. So when the toilet clogs, you will have to take the extreme measure of augering.

Some Concerns Over The Small Flushing Volume

With only 0.8 gallons of water, the vacuum flush plays an important role in moving waste out of the toilet. That’s great, but after the waste left the toilet, where should it go?

Waste should not end up in the drain pipes. It has to travel all the way into the septic tank.

There is concern that the 0.8 gallons of water may not be enough to convey waste as far as those toilets with higher flush volume. Especially on a long horizontal run that stretches over 20 feet long to reach the vertical stack.

However, this hardly poses a problem for the residential drainage system, which rarely goes beyond 10 feet before the vent stack. If it does extend ridiculously far, even your existing 1.6 gpf or 1.28 gpf will have problems with waste conveyance.

This scenario of a super long horizontal run will never and shouldn’t happen for any residential property. There are stringent plumbing codes that lay out the corresponding pipe run distance versus fall angles (or gradient) and pipe sizes for bathroom fixtures like toilets in residential properties.

Drainage Inspection
Image source:

The respective professionals who build the drainage system should have worked out the complete sewage system in compliance with the regulations. You should never have to be concerned with such technicality.

Before you could even take the first flush, the entire sewage system in your house will have to go through some tests and inspection by plumbing consultants. Even on an existing property purchase, a home inspection process to evaluate the integrity and functionality of the entire drainage system is mandatory before completing the transaction.

So relax, you are good to go with this ultra high-efficiency Niagara Stealth toilet for your home. You can safely replace any toilets in your house with this lean and mean human waste removal machine.

Popular Niagara Stealth Models You Can Buy Online

There are a total of 11 models for this Niagara Stealth toilet which include the 0.95 GPF models. But only the models that are available on Amazon is listed here, which are also available on Home Depot and Lowe’s.

The other models you will have to check on Niagara Conservation’s website to know where you can buy them.

Niagara The Original Stealth® – 0.8 GPF Single Flush 12” Elongated Toilet

Niagara 77001WHCO1Model: 77001WHCO1 Elongated Bowl
Bowl shape: Elongated
Bowl height: 17 inches
Flushing system: Vacuum-assisted, single flush
Flushing capacity: 0.8 GPF
Flush handle: Top push-button
Rough-in: 12 inches
Overall dimension: 31″ (H) x 28.875″ (L) x 18.25″ (W)
Certification: WaterSense, ADA Compliant
*Bowl Part Number: N7717
*Tank Part Number: N7714

Check Price On Amazon

*The 77001WHCO1 model is a combination of N7717 (Bowl) and N7714 (Tank). You can purchase them separately for replacement. Or will it be cheaper to buy the tank and bowl separately versus getting the complete model 77001WHCO1? You can compare prices to get the best deal.

Niagara The Original Stealth® – 0.8 GPF Single Flush 12” Round Toilet

Niagara 77002WHCO1Model: 77002WHCO1 Round Bowl
Bowl shape: Round
Bowl height: 16 inches
Flushing system: Vacuum-assisted, single flush
Flushing capacity: 0.8 GPF
Flush handle: Top push-button
Rough-in: 12 inches
Overall dimension: 30″ (H) x 27″ (L) x 18.25″ (W)
Certification: WaterSense, ADA Compliant
*Bowl Part Number: N7716
*Tank Part Number: N7714

Check Price On Amazon

*The 77002WHCO1 model is a combination of N7716 (Bowl) and N7714 (Tank). Like the elongated bowl model, you can buy the tank and bowl separately. Always compare prices to get the best deal.

Niagara One-Piece Stealth® – 0.8 GPF Single Flush Elongated Toilet

Niagara N7711Model: N7711 One-Piece & Skirted
Bowl shape: Elongated
Bowl height: 15.5 inches
Flushing system: Vacuum-assisted, single flush
Flushing capacity: 0.8 GPF
Flush handle: Top push-button
Rough-in: 12 inches
Overall dimension: 28.5″ (H) x 29.5″ (L) x 17.25″ (W)
Certification: WaterSense

Check Price On Amazon


The two most commendable features that stand out from this Niagara Stealth toilet are the quiet flush and the large water surface area. The latter is a result of a pressurized trapway that leads to a higher water level in the bowl.

If you go by the conventional design of a gravity flush toilet, a 0.8 GPF can hardly yield an 8″ x 6″ water surface in the bowl. And this size is rather close to the TOTO Drake II 1.0 GPF toilet which is at 8-7/8″ x 6-7/8″. So despite the smaller water volume, there is no compromise here.

And the low noise level of the flush will appease the light sleepers and the critics of loud toilet flushing. They will love the quiet tank refill as well since the refilling happens under water.

The rest of the features offer convenience and options to meet almost every need. Like the choice of 3 bowl heights, push-button or side handle and even a dual flush option. And the large footprint of this Niagara Stealth will be able to cover the ugly traces left by your old toilet.

So whether you decide to get the 2-piece or 1-piece, installation is easy and does not require any special tools. They even have the 10″ rough-in model with a compact size to fit in any small bathroom.

And if you are sick and tired of cleaning toilets, the one-piece and skirted model will cut down cleaning time tremendously. With all the flat surfaces, no dirt can evade your eyes, and a few easy wipes will return you a sparkling clean toilet.

So there you have it, a less than 1.0 gpf gravity flush toilet that doesn’t compromise on flush performance. Despite the snag at clearing clogs, there isn’t much imperfection you can pick on.

And coming from an organization which is best known for producing water-reducing green products and its water conservation effort, you just can’t go wrong.


  1. Alas no; it disappeared from the market by about 1980, I’m not sure why, and most Brits now have only ever known the washdown. The only traces are in plumbing forums, and a surprising number of YouTube videos of vintage finds!

  2. The Propelair is an interesting concept, though I think the seat and lid seals will be a pain to keep clean. I wonder if it’s noisy.

    Wikipedia has a surprisingly good description of a double trap siphon, which looks similar to the Niagara: “Bomb” is the term for the aspirator that creates the vacuum between the traps. It is a common fail point over time, but fairly cheap to replace.

    • Do they still produce the double trap in the UK? Or there is a newer version of it?

  3. From your diagram and description, this technology looks like a double trap siphon, or “siphon bomb” which was popular in the UK some time in the mid-century. Its flush was supposed to be very quiet, with no gurgle when the siphon seal is broken. Is that what this is? If so, it’s pretty cool; I’m not aware of another double trap design currently sold anywhere.

    • Hi Tony77.

      Not sure about the siphon bomb. Yes, you are right about the flush being quiet and no gurgling at the end. Actually I’m more impressed with Propelair which uses only 1.5 liters (0.4 gallons) of water. Wonder if they have plans for the US market. 🙂

  4. I have a question my niagara stealth toilet has weak flush,what can I do?

  5. Can’t you use a rubber plug to block the “Transfer Tube” from inside at the base of the tank, and then use a plunger to clear any clogs? I’m sure that without a rubber stopper, bowl waste could work it’s way into the tank through the “Transfer Tube” depending on where the clog is located.

    • @G.R. Hart

      If you know what you are doing with blocking the transfer tube inside the tank, yes. But not every user can or are willing to do that. Besides you also run the risk of introducing foreign objects, debris, …whatever into the tube which is a no no. The safest is still to auger if the toilet gets plug.

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