Tenant never transfered utility in his name

[Mark Allen]

Renting out an apartment in California. A tenant moved in 2 years ago and I have recently come to find out he never tranfered the electricity into his name. Its in the lease that power and gas are tenants responsibility. I understand it's my fault I am barley realizing now that I have been paying the bill. After notifying the tenant he has tranfered it in his name however now I am wondering if I can charge him with the 24 months of billing that I paid for, a total of $1,800.00. Are there any legal restrictions regarding what I can and can't do in this situation?