As you know, the initial calculation of child support is done at the time the original child support order is entered. However, the law recognizes that circumstances, as well as income and expenses, may change over time. The process of updating an existing child support order to reflect these changes is called a modification.

The San Mateo County Department of Child Support Services must attempt to modify an existing child support order if a new estimated child support amount changes by at least $50 or 30 percent. This means a $50 or 30 percent change up OR down. If you think a change in your income, the other parent’s income, or some related expense necessitates a change in the support amount, your first step should be to run the numbers through a new child support calculation. If the resulting figure differs from the current child support order by more than $50 or 30% (which ever is less) either way, a modification through the Department of Child Support Services may be in order.

You can also file a court motion for review of your child support order on your own or through the Family Law Facilitator’s Office. You will be given a court date and must also furnish a set of the filed motion for modification to the Department of Child Support Services.
Some of the more common situations that may lead to a modification include:

  • a significant change in parental responsibility time, such as the number of nights a child spends at a parent’s residence
  • a parent’s loss of employment
  • the return of a parent to school

Remember, though, that the key factor is still whether the event in question leads to a continuing change in the support order of at least $50 or 30%, which ever is less. The above events may—or may not—by themselves lead to a change in the amount.

You may think you are entitled to a modification if your ex-spouse has remarried. However, the guidelines only take into account the incomes of the two parents of the child in question. So it doesn’t matter if your ex marries a brain surgeon who makes a fortune—that income generally is not counted in your child support calculation.

Likewise, if you were to remarry someone who had children, you may want to receive credit for the amount of money your new household devotes to your stepchildren. But you can’t. Again, the relevant incomes are those of the children’s parents—in this case, your new spouse and her ex. You can claim these children as a deduction from your gross income for purposes of child support only if you legally adopt them.

If you believe you are entitled to a modification of your support amount, you may contact the San Mateo County Department of Child Support Services at 1-866-901-3212 to request an application to have your court order reviewed. Remember, you may also try to bring a legal action to modify your support order to court independently, with or without the assistance of an attorney. For more information on this process, please contact the Family Law Facilitator’s Office.