Fam. Code, § 4504

(a) If the noncustodial parent is receiving payments from the federal government pursuant to the Social Security Act or Railroad Retirement Act, or from the Department of Veterans Affairs because of the retirement or disability of the noncustodial parent and the noncustodial parent notifies the custodial person, or notifies the local child support agency in a case being enforced by the local child support agency pursuant to Title IV-D of the Social Security Act, then the custodial parent or other child support obligee shall contact the appropriate federal agency within 30 days of receiving notification that the noncustodial parent is receiving those payments to verify eligibility for each child to receive payments from the federal government because of the disability of the noncustodial parent. If the child is potentially eligible for those payments, the custodial parent or other child support obligee shall apply for and cooperate with the appropriate federal agency for the receipt of those benefits on behalf of each child. The noncustodial parent shall cooperate with the custodial parent or other child support obligee in making that application and shall provide any information necessary to complete the application.

(b) If the court has ordered a noncustodial parent to pay for the support of a child, payments for the support of the child made by the federal government pursuant to the Social Security Act or Railroad Retirement Act, or by the Department of Veterans Affairs because of the retirement or disability of the noncustodial parent and received by the custodial parent or other child support obligee shall be credited toward the amount ordered by the court to be paid by the noncustodial parent for support of the child unless the payments made by the federal government were taken into consideration by the court in determining the amount of support to be paid. Any payments shall be credited in the order set forth in Section 695.221 of the Code of Civil Procedure.

(c) If the custodial parent or other child support obligee refuses to apply for those benefits or fails to cooperate with the appropriate federal agency in completing the application but the child or children otherwise are eligible to receive those benefits, the noncustodial parent shall be credited toward the amount ordered by the court to be paid for that month by the noncustodial parent for support of the child or children in the amount of payment that the child or children would have received that month had the custodial parent or other child support obligee completed an application for the benefits if the noncustodial parent provides evidence to the local child support agency indicating the amount the child or children would have received. The credit for those payments shall continue until the child or children would no longer be eligible for those benefits or the order for child support for the child or children is no longer in effect, whichever occurs first.