TOTO limited warranty coverage
TOTO's limited warranty for residential showerheads covers defects in materials and workmanship for one year from the date of purchase (some premium models carry longer coverage -- verify with the product documentation). Contact TOTO customer service at 1-888-295-8134 with the model number and purchase information. TOTO ships replacement parts through the warranty process or through authorized plumbing supply distributors.
Spray face descaling -- Comfort Wave channels
TOTO's Comfort Wave channels are precision-molded into the spray face and can accumulate mineral deposits in hard water areas that affect spray pattern quality. To descale: soak the spray face (removable by unthreading the face ring counterclockwise on most models) in a 1:1 white vinegar and water solution for 30-60 minutes. Use a soft toothbrush to clean the channel openings. Rinse thoroughly with clean water before reinstalling. In areas above 200 ppm hardness, monthly descaling prevents significant pattern degradation.
Mode collar O-ring
On multi-spray TOTO models (TBW series), the mode selection collar rotates on an O-ring seal. If the collar leaks at the spray face perimeter (water running down the outside of the showerhead rather than through the nozzles), the collar O-ring is worn. Request the replacement O-ring by model number from TOTO customer service. The repair involves disassembling the collar ring from the body (typically 3 screws behind the collar ring), replacing the O-ring, and reassembling.
Inlet washer
The flat rubber inlet washer (at the shower arm connection) is the most common source of drips after installation. It is a standard 5/8" OD flat rubber washer available at any hardware store ($1-$2). If the connection drips and additional tightening does not resolve it, replace this washer. Remove the showerhead from the arm, pull out the old washer from the inlet, insert the new washer, and reinstall.