Dragon Series 1-3 by Allyson James

Dragon 01 – Dragon Heat
Lisa Singleton has an unusual roommate-a fifty-foot dragon named Caleb who has glittering scales and a bad attitude. Little does she know that Caleb is actually a powerful warrior sent to protect her from those out to steal her magic and destroy the world. Or that Caleb can take the human form of a sexy hunk. Now, if he doesn't stop distracting her with those gorgeous bedroom eyes, they may not have time to stop their enemies before all of existence is wiped out. At least Lisa and Caleb will have savored every last minute.

Dragon 02 – The Black Dragon
Saba has finally managed to put the black dragon Malcolm out of her mind and out of her life. But an assault by an evil white dragon in human form on a bay area train forces her to use the magic Dragon's Tears Malcolm left behind to call him for help. Malcolm is still as tall and darkly sensual as ever, and Saba fears falling for him again. But Malcolm has returned to the human world for Saba's help--his considerable powers are being drained and he needs Saba's special witch magic to save him.

Dragon 03 – The Dragon Master
Carol Juan doesn't really believe that her grandmother's friends are dragons, though she'll admit that Caleb and Malcolm are unusual. But when a Fire Dragon, a very rare creature who can not only take human form but turn himself into pure flame, seeks her out, she has to put her disbelief behind her. The arrogant and wild Seth teaches Carol not only about fire dragons, but about her own latent mage powers that pulled him instinctively to her. The secret of the Fire Dragon might help Carol win the day or be the means to her destruction.