Pressure-Assisted Toilets
Updated February 20, 2026
Use compressed air in a sealed tank to create a powerful flush. Common in commercial settings and homes where clog prevention is a priority.
Overview
Pressure-assisted toilets use compressed air inside a sealed tank vessel to force water into the bowl with more power than gravity alone. The result: a stronger, more complete flush that clears waste more effectively and resists clogging. Common in commercial settings and increasingly available for residential. The tradeoff: significantly louder flush (sounds like a commercial toilet), higher cost, and repairs require specific parts. Best for households with frequent clogging problems or where maximum flush performance matters more than quiet operation.
Pros & Cons
- Powerful flush
- Rarely clogs
- Water efficient
- Louder than gravity-fed
- More expensive to repair
- Higher purchase cost
Key Features
- Compressed air assists gravity for a more powerful flush
- Superior waste clearing -- virtually eliminates clogs
- Uses less water per flush (1.0-1.28 GPF) while moving more waste
- Sealed pressure vessel inside the tank (not a standard tank)
- Louder than gravity-fed -- noticeable difference in noise level
Sizing & Selection
Same rough-in and exterior dimensions as standard toilets. 12-inch rough-in. Round or elongated bowl. The pressure vessel sits inside the tank, so the tank looks standard from outside. Requires minimum 25 PSI water pressure to charge the vessel -- homes with very low pressure may not be able to use pressure-assisted.
Installation
Same physical installation as gravity-fed. The difference is inside the tank: a sealed pressure vessel replaces the open tank. Water fills the vessel, compressing the air inside. When you flush, the compressed air expels water forcefully into the bowl. No special plumbing beyond standard toilet connections. Requires adequate water supply pressure (25+ PSI).
Maintenance
- The pressure vessel has fewer moving parts than a gravity system -- no flapper to replace.
- If the flush weakens, the vessel or cartridge may need replacement (-100 for the cartridge).
- Check water supply pressure annually -- low pressure means a weak flush in pressure-assisted models.
- Repairs require brand-specific parts. Fluidmaster and Sloan are the main manufacturers of pressure-assist mechanisms.
Buying Tips
- American Standard Cadet and Kohler Highline with Sloan Flushmate are the most available residential models.
- Test the flush noise before buying if possible. Pressure-assisted toilets are noticeably louder than gravity-fed.
- Do not install in a house with water pressure below 25 PSI -- the pressure assist will not work properly.
- Budget -600. More expensive than standard gravity-fed but less expensive than high-end one-piece gravity models.
- If clogging is your main problem, try a high-performance gravity toilet first (TOTO Drake, American Standard Champion 4). Many solve the problem at lower cost and noise.