"ianjones" wrote in message
oups.com...
.
.. Can I run a cold and hot line
off the inputs to my WH and just tap into that drain for the sink?


No, yes.

If you tap into the inputs, you only get cold water. Tap the input for
cold, the output for hot. (yes, I know you meant that)

Yes, you can tap into that pipe for the drain.

If
so, what are best practices for going from a standard drain to a larger
drain pipe?

There are usually adapters that will go onto the drain pipe as a saddle. You
use a hole saw to make the hole in the side, strap on the saddle, attach the
drain and trap as normal.