What Counts as a Substantial Change in Circumstances for Child Support in Idaho

By the FigureMyTax Editorial Team · How we calculate

To modify Idaho child support you need a substantial and material change of circumstances, and only installments after you file can change. There is no percentage line, and a changed guideline amount may itself qualify.

What is a substantial and material change of circumstances for child support in Idaho?

The provisions of any decree respecting maintenance or support may be modified only as to installments accruing after the motion for modification and only upon a showing of a substantial and material change of circumstances (Idaho Code 32-709(1)). The statute does not define the phrase or list changes. The Idaho Child Support Guidelines add that when the amount of support under them changes, it may constitute a substantial and material change of circumstances, and that a support order may be changed to provide for health insurance that was not in it (Rule 126(d)).

Is there a percentage rule in Idaho?

No. Neither the statute nor Rule 126 sets a percentage change that triggers modification. A $100 gap is a very different change on a $500 order than on a $2,000 order:

The Idaho child support modification calculator therefore shows the gap and what it adds up to, and leaves the call to the court.

Is the guideline amount binding?

It is presumed correct. The legislature authorized the Supreme Court to adopt guidelines, and there is a rebuttable presumption that the amount from applying them is the amount to award unless evidence shows that applying them would be unjust or inappropriate. A judge who departs must make a written or specific finding on the record (32-706(5)).

Do new children count?

Not for the party asking to modify. When the Supreme Court adopts guidelines it must provide that in a proceeding to modify an existing award, children of the party requesting the modification who were born or adopted after the existing order are not considered (32-706(5)).

What is the minimum order?

Rule 126 says there is a rebuttable presumption that a minimum amount of support is at least $50 a month per child, that the obligation should rarely be set at zero, and that where the paying parent’s monthly income is below $800 the court should review incomes and living expenses closely to avoid denying the parent a minimum subsistence level.

From what date can the order change?

Only installments accruing after the motion for modification can be modified (32-709(1)). Every month before filing is lost:

Federal law also bars retroactive modification of support already due (42 U.S.C. 666(a)(9)).

What goes into the guideline calculation?

Guidelines income is the gross income, before taxes, of the parents, plus employment benefits and potential income where they apply. Gross income includes salaries, wages, commissions, bonuses, dividends, pensions, interest, trust income, annuities, social security, workers’ compensation, unemployment insurance and disability benefits, alimony, veterans’ benefits and education grants. Overtime or second-job income is excluded only if the court finds specific conditions are met (Rule 126(e)). Bring proof of every source, because a change in any of them changes the guideline amount.

What happens next?

Read how to modify child support in Idaho for the filing steps, and check what stays owed with the Idaho arrears calculator.

Frequently asked questions

Official sources

• Idaho Code 32-709: modification of support
• Idaho Code 32-706: child support; guidelines presumption
• Idaho Rules of Family Law Procedure, Rule 126: Idaho Child Support Guidelines
• Idaho Code 32-1204: income withholding
• 42 U.S.C. 666(a)(9): no retroactive modification of support already due

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