In CA, in January 2014, the law states:

§4992.3. UNPROFESSIONAL CONDUCT; EFFECT ON LICENSEE OR REGISTRANT

(l) Engaging in sexual relations with a client or with a former client within two years from the termination date of therapy with the client, soliciting sexual relations with a client, or committing an act of sexual abuse, or sexual misconduct with a client, or committing an act punishable as a sexually related crime, if that act or solicitation is substantially related to the qualifications, functions, or duties of a clinical social worker.

I thought I read somewhere that social relationship was 2 years and sexual was 7...not sure where I read that though

But just written communication...I think that's up to the T. I know I was allowed to stay in contact with my last T (though I didn't want to), the T before her (which I still write to), and my counselor from the board and care I stayed at (I am friends with her on Facebook and have her personal email).

I talked to my current T about contact after termination, and she said I can always stay in contact with her. And that if she's still practicing and in the area, I can go back and see her on an "as needed basis" for therapy.