Niagara Stealth Sabre 0.8 GPF Two-Piece Elongated Vacuum-Assist Toilet

The Niagara Stealth Sabre positioning

The Stealth Sabre (UPC C22.303.01, model N7717) is the toilet that defines Niagara Conservation as a brand — the lowest-flow gravity toilet IAPMO-certified in the US residential market. At 0.8 gallons per flush, the Stealth Sabre uses half the water of the federal 1.6 GPF maximum and 38% less than the WaterSense 1.28 GPF threshold. Over a 5-year period, a two-person household using a Stealth Sabre saves roughly 23,000 gallons compared to a standard 1.6 GPF toilet — and roughly 7,500 gallons compared to a 1.28 GPF model.

At $280-$360, the Stealth Sabre is priced comparably to Kohler Cimarron and TOTO Eco Drake but with dramatically lower water use. The combination of low water + rebate eligibility makes the Stealth Sabre the cheapest toilet to own over 5 years in rebate-eligible CA/AZ/TX utility districts — sometimes free or even net positive after rebates and water-bill savings.

How the vacuum-assist trapway actually works

The Stealth Sabre's engineering trick is the vacuum-assist trapway. As water exits the tank during flush, it creates a partial vacuum behind it in the trapway, accelerating the waste through. The vacuum acceleration is what enables 0.8 GPF flush performance comparable to a 1.28 GPF gravity-only toilet.

The mechanism components:

• Vacuum chamber dome — sealed plastic dome above the flush valve, creating the partial vacuum during flush
• Specialized flush valve — calibrated to release 0.8 GPF over a precise interval that maintains vacuum
• Stealth-specific flapper — Niagara part 77000WHA-F. Has a unique seal profile that maintains vacuum (universal Korky/Fluidmaster flappers will NOT work — they don't maintain vacuum integrity)
• Re-engineered bowl trapway — slightly tighter S-curve than typical residential, optimized for vacuum-accelerated flow
• Vent hole on dome top — small atmospheric vent that prevents over-pressurization while allowing vacuum during flush

Performance characteristics:

• MaP score: 800g — well above WaterSense 350g threshold, comparable to TOTO Eco Drake and Kohler Cimarron at higher GPF
• Flush time: ~6-7 seconds — the audible "whoosh-suck" sound is the vacuum activating
• Bowl-cleansing: the vacuum-accelerated water provides comparable cleansing to 1.28 GPF gravity flushes
• Service life: 10-15 years for the vacuum dome; standard flapper at 5-7 years

The rebate math (why Stealth Sabre is often the cheapest toilet to own)

A Niagara Stealth Sabre retails for ~$300. In rebate-active utilities, the rebate often runs $100-$200 per fixture. Net out-of-pocket can drop to $100-$200. Over 5 years, the water-bill savings vs 1.28 GPF run $40-$120/year (assuming standard residential water rates) or $100-$250/year in drought-tiered pricing zones.

Active rebate examples (2026 — verify with your specific utility):

• LADWP (Los Angeles): $100 for sub-1.0 GPF toilets (Stealth Sabre qualifies); $40 for 1.28 GPF only
• EBMUD (East Bay): $100 per fixture
• SFPUC (San Francisco): $200 for ultra-low-flow
• SRP (Salt River Project, AZ): up to $200
• San Antonio Water System (TX): $100 per replacement of pre-1992 toilets
• SNWA (Southern Nevada): up to $150 for ultra-low-flow
• Tucson Water: $75 per WaterSense toilet, +$25 for Most Efficient (Stealth Sabre qualifies)

Combined with water savings, payback in rebate-eligible drought-zones is typically 2-3 years.

The Stealth Sabre variant matrix

What's in the box

• Tank with pre-installed vacuum chamber dome assembly + Stealth-specific flapper
• Bowl pre-drilled for 12" rough-in
• Tank-to-bowl gasket and brass bolts
• Chrome trip lever
• Wax ring NOT included
• SoftClose seat NOT included — Bemis 1500EC ($35) recommended
• Installation manual
• WaterSense Most Efficient certification documentation (needed for rebate claims)

Install requirements and procedure

• Rough-in: 12 inches (standard).
• Weight: ~84 lbs total (tank ~36, bowl ~48).
• Standard two-piece install — same procedure as Kohler Cimarron or TOTO Drake II.
• Water supply: standard 3/8" compression-fit — no special plumbing.
• Floor flange: standard 12" rough-in. The Stealth Sabre is more sensitive to floor flange height — verify flange is at finished-floor level, not protruding above or recessed.
• Drain line: if your home has older galvanized or partially obstructed drain lines, test the Sabre after install to verify clearance. The 0.8 GPF flush has less volume to push through partial obstructions than 1.28 GPF alternatives.

What owners report (5-15 year ownership)

• The water savings are real and meaningful in monitored-water households. California owners specifically report 25-30% reduction in water-bill toilet use after switching from 1.28 GPF.
• The vacuum-activation "whoosh" sound is the most-commented feature in reviews — owners describe it as a satisfying sound that confirms the flush is working.
• Bowl-cleansing performance is acceptable for normal-use households. Heavy paper-use households occasionally double-flush.
• Older homes with partial drain-line obstructions sometimes experience clearance issues — the 0.8 GPF flush doesn't have momentum to push through what 1.28 GPF might clear. If you have documented drain issues, consider the Niagara Liberty (1.28 GPF) instead.
• Vacuum dome assembly service life: 10-15 years. When the dome eventually fails (mineral buildup or seal degradation), replacement is Niagara part 77000WHA-S at $45 + 30-minute DIY.
• Stealth-specific flapper service life: 5-7 years. Niagara 77000WHA-F at $15.
• The 5-year warranty on vacuum-assist mechanism is meaningful — Niagara honors replacement claims for vacuum dome failures within 5 years.

Where Stealth Sabre wins

Where Stealth Sabre loses

• Standard ceramic glaze — no CeFiONtect/Pure-Clean/EverClean alternative on Stealth Sabre line. Hard-water spots accumulate faster.
• Older home drain compatibility — partial obstructions may need higher GPF for reliable clearance
• Niagara-proprietary vacuum dome — replacement at end-of-service-life requires Niagara-direct sourcing (5-7 day lead time)
• Limited retail availability outside of Home Depot Pro Desk and plumbing supply channels

The verdict

Buy Stealth Sabre if:

• You're in a rebate-eligible utility district (CA, AZ, TX, NV, parts of FL) — Stealth Sabre is among the highest-rebated toilets
• Water conservation is a priority (drought-zone residence, LEED-certified building, environmental priority)
• You want sub-1.0 GPF flush without pressure-assist noise
• You have a modern home or recently-serviced drain lines (no partial obstructions)
• You want the lowest-cost-to-own toilet in rebate-eligible markets (rebate + 5-year water savings often exceeds purchase price)

Skip and choose Niagara Liberty (1.28 GPF) if:

• Older home with documented drain-line obstructions — 1.28 GPF clearance more reliable
• Heavy paper-use household where 0.8 GPF would require frequent double-flushing
• Same Niagara brand at $80-$100 less

Skip and choose Kohler Cimarron / TOTO Eco Drake if:

• You don't qualify for utility rebates and water rate is low
• You want CeFiONtect/EverClean hydrophobic glaze upgrade option
• Brand recognition matters for resale value

Warranty

Niagara Stealth Sabre residential warranty: 5 years on tank trim, lifetime on porcelain, 5-year warranty on vacuum-assist trapway mechanism. Niagara honors vacuum dome replacement claims directly — call Niagara Customer Service (1-800-831-8383) with serial number and proof of purchase.

Pricing reality (2026)

Stealth Sabre N7717 (White, elongated, Universal Height): $280-$340. Home Depot Pro Desk: $289-$329. Lowes: limited availability. Build.com: $269-$319. Direct from Niagara: $279-$319. Biscuit/Bone variants +$30-$40. Net cost after rebates in CA/AZ/TX: $80-$240 — making Stealth Sabre often the cheapest premium-brand toilet to own.