How to Modify Child Support in New Hampshire: Filing Steps and Effective Date

By the FigureMyTax Editorial Team · How we calculate

To modify New Hampshire child support, file a petition and give the other parent notice. A change is not effective before notice, an overpayment after notice is refunded, and 3 years after the last order no substantial change is needed.

How do you modify child support in New Hampshire?

1. Run the guideline amount in the New Hampshire child support calculator and see the gap in the modification calculator.
2. File a petition to modify with the court that issued the order, or with the department if it issued a legal order of support (RSA 458-C:7, I(a)).
3. Give the other parent notice. A change is not effective before notice was given (458-C:7, II).
4. Show a substantial change unless 3 years have passed since the last order.
5. Keep paying the existing order until it is changed.

What counts as notice in New Hampshire?

Service as specified in civil actions, or acceptance of a copy of the petition, as long as the petition is filed no later than 30 days after the acceptance and the petitioner provides proof of acceptance by a certified mail receipt (458-C:7, II). A casual copy is not enough, so use service or a certified mail receipt.

What if I overpaid after I gave notice?

When a modification results in an overpayment of support, the court orders, absent a showing of undue hardship, the obligee to reimburse the obligor directly or orders an adjustment to the modified order until reimbursement is satisfied. It covers only the overpayment after notice, takes effect 30 days after issuance unless either parent asks for a separate hearing to set the amount and frequency (458-C:7, III).

How does the New Hampshire department review work?

The department notifies parties to orders payable through it, at least every 3 years, of their right to request a review and, if appropriate, to apply for adjustment; it reviews every order with a TANF assignment at least every 3 years and applies for adjustment under the guidelines if appropriate (458-C:7, I(b)-(c)). You can also ask for a review on your own.

Who enforces support in New Hampshire?

The Department of Health and Human Services enforces support when a child receives public assistance or when the commissioner accepts an application from a parent who is not on assistance (RSA 161-B:3). Ask whether your case is open.

Do the medical support terms change too?

Each order must include findings on health care coverage and uninsured expenses (461-A:14, IX). If coverage is now accessible or no longer available at a reasonable cost, raise it in the same petition.

Do I need a lawyer?

Not necessarily. The circuit court clerk can explain forms, and the department can help if it enforces your order, but a licensed New Hampshire attorney can advise on your case.

How much does a late petition cost? An example

If notice happens 3, 6 or 9 months after your change, the relief you lose at a $300 monthly difference is:

What happens to unpaid support while the petition is pending?

It stays owed as a judgment. See whether New Hampshire arrears can be changed and add up your balance.

Frequently asked questions

Official sources

• RSA 458-C:7: modification of order
• RSA 461-A:14: support
• RSA 458-C:2: definitions, including gross income
• RSA 458-C:5: adjustments under special circumstances
• 42 U.S.C. 666(a)(9): no retroactive modification of support already due
• RSA 161-B:3: duty of the department to enforce support

This is general information, not legal advice. It is based on the cited New Hampshire statutes, rules and court opinions, and every case turns on its own facts. Confirm how the law applies to your situation with a licensed New Hampshire attorney.