Tankless toilets eliminate the visible tank entirely — water is supplied directly from the building water line through a pressurized flush valve. The aesthetic is the cleanest possible: just a bowl mounted to the floor or wall with no visible tank above. Almost universally found in commercial restrooms (where the Sloan flushometer is the standard), tankless residential toilets are a premium-niche category that's growing in luxury residential applications.
Two distinct categories exist for residential use: integrated smart tankless (TOTO Neorest, Kohler Karing — these have small internal pumps and reservoirs but no visible tank) and true commercial-style flushometer residential (rare in residential but available — requires high-pressure water supply, typically only feasible in homes with 50+ PSI water pressure).
The clear use case for residential tankless is luxury bathroom design where the aesthetic matters. The build cost premium over a standard toilet is significant — $3,500–$8,000 for an integrated smart tankless vs. $300–$800 for a traditional gravity-feed two-piece.
Water pressure is the make-or-break consideration. Residential gravity-feed toilets work at any water pressure from 20 PSI up. Tankless flushometer toilets need 35+ PSI minimum, ideally 50+ PSI. Homes on well water or with marginal municipal pressure may not be candidates. Check your water pressure (using a pressure gauge that screws onto an outdoor hose bib, $15) before specifying a tankless toilet.
Top picks: TOTO Neorest 750H ($5,999) for integrated smart tankless, TOTO MH Wall-Hung ($899) for wall-hung tankless aesthetic at lower price point, Kohler Veil Wall-Hung ($899+) as the Kohler equivalent.