A treatment plan is a written plan, designed by the consumer and practitioner, listing attainable treatment goals that can be measured by objectives. This plan should be person-centered and trauma-informed. It should always use S.M.A.R.T. Goals.
A treatment plan should be reviewed every 30-90 days in treatment depending on the treatment episode length.
To read what Substance Abuse and Mental Health Services Administration (SAMHSA) says about treatment planning, click here or here.