Start with the existing connection, not the showroom display
This checklist is for a planned fixture purchase, not deciding whether a running or blocked toilet needs replacement. Keep the current toilet installed while gathering measurements. Photograph the whole fixture and safely visible model information, then save the candidate toilet's exact model number and dimensional drawing. A floor-mounted toilet, a wall-hung toilet and a rear-outlet model are not interchangeable because their styling looks similar. If you cannot identify the connection, ask the provider to verify it before ordering.
Measure the rough-in from the finished wall
For a conventional floor-mounted toilet, measure from the finished wall behind the toilet—not the face of the baseboard—to the center of the floor-mounting bolts. KOHLER identifies 12 inches as the most common rough-in, with 10- and 14-inch options also available; common does not mean your bathroom has that dimension. Do not measure to the front edge of the bowl. If the bolts are concealed, there are several bolt positions or wall trim prevents a reliable reading, record that uncertainty rather than rounding to a convenient size. The installer should confirm compatibility with the specific product.
Check the entire footprint and usable space
Compare the manufacturer's overall depth, width and tank height with the room. Note the door swing, vanity drawers, nearby tub and any shelf above the tank. Round-front bowls often save space, but a compact elongated model may have different overall dimensions from another elongated toilet. Check the drawing rather than buying by shape alone. A smaller base can expose old flooring marks or an unfinished area concealed by the current toilet. Room measurements help with selection; they do not establish that required clearances or accessibility provisions are satisfied.
Choose seat height for the people who will use it
Compare finished seat height, not just the ceramic bowl height or a marketing name. A taller seat may help someone who has difficulty sitting down or standing up, while a lower one may suit another user better. Check whether the seat is included and whether its shape and mounting suit the fixture. A product described as accessible does not make the entire bathroom accessible: approach space, transfers and other features need their own assessment where applicable.
Check supply access and the complete product list
Share the location of the existing shutoff and supply connection with the installer. A skirted base can affect access, and some models use product-specific mounting or adapter systems. Confirm those requirements before purchase rather than assuming an old connection can be reused. Ask whether the carton includes the tank, bowl, seat and required mounting hardware. The seal, supply connection and any flange or valve work still need confirmation. Powered toilets or seats require separate professional assessment of their electrical and water requirements; this checklist is not wiring guidance.
Use efficiency certification without assuming a rebate
EPA WaterSense labeling evaluates both water efficiency and flushing performance through independent certification. Check the exact model in EPA's product search rather than relying only on a retailer's low-flow description. Compare the manufacturer's flush specifications, especially for dual-flush products. Any rebate depends on your own water supplier's current eligibility and purchase rules; verify those before buying. Neither a label nor a new fixture guarantees a particular bill reduction or fixes a downstream drain restriction.
Send the installer a purchase-ready checklist
Provide the model and product drawing, rough-in reading, room measurements, supply photo, desired seat height and delivery status. Ask who supplies materials, who removes the old toilet and how unsuitable parts or concealed flange and floor damage will be handled. Published replacement labor is not an all-inclusive fixture purchase. Use the service pages for current labor and visit-fee terms, including scheduled-morning exceptions, and confirm the applicable offer before booking.