Niagara offers 14 4-inch flush valve toilets models in the lineup we track. This page is the Niagara-specific cut of the broader 4-inch Flush Valve Toilets (Champion 4 et al.) toilets category — same product class, narrowed to the Niagara catalog only.

About Niagara

Niagara — Niagara commercial water heaters.

For the complete Niagara lineup across all sub-types and capacities, see the Niagara Toilets hub.

Niagara 4-inch Flush Valve Toilets (Champion 4 et al.) models we track

Niagara Stealth Sabre 0.8 GPF Two-Piece Elongated Vacuum-Assist Toilet (N7717) — Niagara Stealth Sabre — the lowest-flow gravity toilet IAPMO-certified in the US. 0.8 GPF vacuum-assist trapway, EPA WaterSense Most Efficient.
Niagara Stealth 0.8 GPF Two-Piece Round-Front Vacuum-Assist Toilet (N7715) — Niagara Stealth Original — the original 0.8 GPF vacuum-assist Niagara. Round-front bowl + UPC C11.301.01.
Niagara Liberty 1.28 GPF Two-Piece Elongated Toilet (N2840) — Niagara Liberty — Niagara's 1.28 GPF mainstream toilet. WaterSense, comfort height, value-tier alternative to Stealth Sabre.
Niagara Phantom 1.6 GPF Two-Piece Elongated Toilet (N2238) — Niagara Phantom — 1.6 GPF traditional gravity flush. Landlord-rebuild grade for installations where rebate eligibility isn't a factor.
Niagara Steaful 1.28 GPF Two-Piece Round-Front Toilet (N7716) — Niagara Steaful — entry-tier 1.28 GPF Niagara. Round-front, comfort height, value-tier WaterSense compliance.
Niagara Power One 0.8 GPF Two-Piece Elongated Vacuum-Assist Toilet (N7720) — Niagara Power One — refined ultra-low-flow toilet with upgraded vacuum-assist trapway. The newer flagship Niagara at 0.8 GPF.
Niagara Stealth Dual-Flush 0.8/1.1 GPF Two-Piece Elongated Toilet (N7718) — Niagara Stealth Dual-Flush — vacuum-assist toilet with 0.8 GPF light flush + 1.1 GPF heavy flush. Average use ~0.95 GPF.
Niagara One One-Piece Elongated 1.0 GPF Toilet (N7950) — Niagara One — sub-1.0 GPF one-piece toilet. Combines water savings + designer one-piece silhouette + WaterSense Most Efficient.

Other 4-inch Flush Valve toilets brands

If you're cross-shopping 4-inch flush valve toilets beyond Niagara, the following brands also ship in this category:

About 4-inch Flush Valve Toilets (Champion 4 et al.) toilets

A 4-inch flush valve is the largest flush valve sold in US residential toilets. The standard residential flush valve is 2-inch or 3-inch; 4-inch is the rare premium specification, found primarily on the American Standard Champion 4 line. The larger valve moves water from the tank to the bowl at much higher velocity than a 2"-3" valve, which means stronger flush performance at the same GPF.

Flush velocity = (tank water volume × valve diameter) / time. A bigger valve = more velocity per gallon of water. For a 1.28 GPF toilet:

2-inch flush valve: flow rate ~30 seconds per gallon
3-inch flush valve: flow rate ~15 seconds per gallon
4-inch flush valve: flow rate ~7 seconds per gallon

The 4-inch valve dumps the entire 1....

For the complete 4-inch flush valve buyer's guide (all brands, full comparison framework), see the 4-inch Flush Valve Toilets (Champion 4 et al.) category hub.

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