I paid my half of the rent, roomate didnt and we both get evicted?

I live in California and moved into my house 2 months ago. My husband and I paid our half of rent and security deposit. Our roomate paid her security deposit and hasn't paid rent for the whole 2 months. She doesn't help with PGE, cable or internet and has since moved in her BF. They put a dead bolt lock on there door, they are doing drugs as well as bringing numerous people in the house that do drugs (she wasn't like this until she moved this dude in the 2nd day we lived here even though she never asked) she has a son and gets SSI for him (even though he's fine) and blew her money on going out to eat, drugs and stuff for her BF leaving my husband and I out in the cold why they use our free utilities as well as a roof over the head. Come today we were served with a 3 day pay or quit notice (she gave us her usual excuses about how she paid rent when we know she didnt). Can my husband and I really get evicted because SHE didnt pay HER rent and we did? Weve talked to the landlord and he said he could try his "best" not to put our names on the eviction. HA! Were on a yr lease.....What can I do? Is this legal?