TMZ.com reports that Charlie Sheen and Brooke Mueller have reached a custody agreement, which includes mutual drug testing. In the case of Sheen and Mueller, it appears the parties volunteered to submit to drug tests. But what if they didn’t volunteer to do so? Could the court order one, or both of them, to take a drug test?

Family Code section 3041.5, provides that “[i]n any custody or visitation proceeding…the court may order any person who is seeking custody of, or visitation with, a child who is the subject of the proceeding to undergo testing for the illegal use of controlled substances and the use of alcohol if there is a judicial determination based upon a preponderance of evidence that there is the habitual, frequent, or continual illegal use of controlled substances or the habitual or continual abuse of alcohol by the parent…”

Thus, the court may order a drug test, but only if it first determines, by a preponderance of evidence, that there is the habitual, frequent, or continual illegal use of controlled substances. Among the ways to show this is a conviction within the last five years for the illegal use or possession of a controlled substance. Family Code section 3041.5.

Once it is established that the court may order a drug test, what type of test might the court order? The short answer is that it must be the least intrusive method. Family Code section 3041.5. This may be, for example, a urine test as opposed to a blood test.

If a test is positive, the parent who took the test has a right to a hearing, if they request one, to challenge the result. Family Code section 3041.5. Even if the positive test is upheld, it doesn’t necessarily mean that the court will issue a custody order in favor of the other parent. This is because, in determining the best interests of the child, the court is required to weigh all relevant factors, only one of which would be the positive drug test.