: Just installed a Toto Drake in the basement where the drain line runs below the slab. I bought the Drake because my parents have a Toto in their basment, and it flushes great. Mine, however, doesn't seem to flush as vigorously. The lavatory sink drains just as fast as the upstairs lavatory so I don't think it's a vent or drain line problem. Any ideas on what might be slowing down the flush or what else I can check?

Larry,
The more clear the main line is, the better any toilet will flush.
Some of the time, when I encounter things slowing down, it can be the main line.
Other things to consider, would be whether the outlet of the trapway is being blocked by the wax seal.
One test you can do, is to hold the lever down and dump the 4+ gallons in the tank in one shot and see how quickly it leaves.

A typical flush uses about 1.5 gallons, when you flick the lever. That should clear anything you put down it.
I suggest balling up some toilet paper and checking the flush that way too.

Most of the action on the Toto, is below the water surface. That large siphon jet, has a strong underwater current.