How to Modify Child Support in Arizona: Filing Steps and Effective Date
To modify child support in Arizona, file a petition under the simplified procedure (for a 15% variance or a medical-insurance change) or the standard procedure. The change takes effect on the first day of the month after notice of the petition.
How do you modify child support in Arizona?
Modification is governed by A.R.S. 25-327 and 25-503 and by Rules 91 and 91.1 of the Arizona Rules of Family Law Procedure. It can be sought in two ways: the standard procedure or the simplified procedure (Guidelines Section XIV).
- Run the new amount in the Arizona child support calculator and check the 15% test in the modification calculator.
- Choose the procedure: simplified if the Guidelines amount varies 15% or more, or for a medical-insurance change; otherwise the standard petition.
- Complete the forms and a sworn Child Support Worksheet with income documentation.
- File and serve the other parent.
- Keep paying the existing order until it is changed.
What forms does the simplified procedure use?
A Petition to Modify (Change) Child Support (Simplified Process), a Request for Hearing (Simplified Process), a Child Support Worksheet, an Affidavit of Financial Information and a Child Support Order, using the Arizona Supreme Court forms or substantially similar ones. The request must be accompanied by a completed and sworn Worksheet and documentation of the incomes. A parent, a person entitled to receive support or the Title IV-D agency can file it.
How long does the other parent have to object?
A parent who disputes the requested modification must request a hearing within 20 days of service in Arizona, or 30 days if service is made outside the state. If a hearing is timely requested, the court must hold it and no order may be modified without it; if none is requested, the court reviews the proof of service and the request and enters an order or sets the matter for hearing (Guidelines XIV.C.5-8).
From what date does an Arizona child support change take effect?
Modifications and terminations are effective on the first day of the month following notice of the petition, unless the court, for good cause shown, orders the change to become effective at a different date not earlier than the filing date (A.R.S. 25-327(A)). Arrears that accrued before notice cannot be changed. Every month before notice is lost:
| Monthly difference | Lost after 6 months | Lost after 12 months |
|---|---|---|
| $100 a month | $600 | $1,200 |
| $200 a month | $1,200 | $2,400 |
| $400 a month | $2,400 | $4,800 |
Federal law also bars retroactive modification of support already due (42 U.S.C. 666(a)(9)).
What is the standard procedure?
A parent, a person entitled to receive support or the Title IV-D agency may petition the court to modify, and the petitioning party must show a substantial and continuing change of circumstances from the date the existing order was filed. It often leads to a conference or hearing.
Can the state agency review my order without a change?
In a Title IV-D case, yes, every three years on request; the department files a petition in superior court to adjust the amount if appropriate (A.R.S. 25-503(G)).
What happens to unpaid support while a petition is pending?
It stays owed. Each installment vests when due and is enforceable as a final judgment, and interest runs (see the Arizona child support interest rate).
Frequently asked questions
How do I modify child support in Arizona?
File a petition to modify under the standard or simplified procedure with a sworn Child Support Worksheet and income documentation, and serve the other parent.
How long does the other parent have to request a hearing on an Arizona simplified modification?
Within 20 days of service in Arizona, or 30 days if service is made outside the state.
From what date can Arizona child support be modified?
From the first day of the month following notice of the petition, or a later date for good cause but not earlier than filing.
Can Arizona child support be changed retroactively?
Not for arrears that accrued before notice of the petition; federal law also bars retroactive modification of support already due.
What forms does the Arizona simplified modification use?
A Petition to Modify, a Request for Hearing, a Child Support Worksheet, an Affidavit of Financial Information and a Child Support Order.
Official sources
- Arizona Child Support Guidelines (Administrative Order 2022-116), Sections XIV and XVII
- Arizona Courts: Arizona Child Support Guidelines
- A.R.S. 25-327: modification and termination of provisions for maintenance, support and property disposition
- A.R.S. 25-503: order for support, modification, termination and judgment on arrearages
- 42 U.S.C. 666(a)(9) and (a)(10): judgments by operation of law and review of orders
A local family law attorney can review your situation — many offer a free consultation.
This is general information, not legal advice. It is based on the cited Arizona statutes, rules and court opinions, and every case turns on its own facts. Confirm how the law applies to your situation with a licensed Arizona attorney.