Why does the handle work backward on my faucet?

The handles work backward because the cartridge stem was installed backwards.

Simply loosen the stem assembly and rotate the cartridge stem 180 degrees and reinstall with care and maintenance.

-Use damp cloth to wipe clean cartridge seat of any build ups

-Use Silicon grease (safe for drinking) onto cartridge rubber rings

-Do not over turn the cartridges, simply hand tight and a quarter turn with a wrench