What Are the Grounds for Modifying Child Custody or Child Support Orders?

Child custody and child support orders are vital components of any divorce or separation agreement involving children. They are meant to prioritize the well-being of the child and provide stability in their upbringing.
However, life is unpredictable. Circumstances change, and what once worked for a family may no longer serve its best interests.
When situations change, parents may wonder if they can change child custody or support orders. At Smolka Law Group in Palantine, Illinois, we help clients in these situations every day.
Here, we’ll explore the legal standards for modifying child custody and child support orders and provide an overview of how courts evaluate modification requests.
Modifying a child custody or child support order isn’t as simple as making an informal agreement between parents. Because these orders are legally binding, any modification must be approved by the court.
The parent requesting the modification typically bears the burden of proof and must demonstrate that a substantial change in circumstances has occurred.
In all custody-related matters, the court’s primary concern is the best interests of the child. This guiding principle also plays a prominent role in evaluating support modifications. If you’re in a situation where a child custody or support order modification is necessary, consulting with a family lawyer, such as one of our attorneys at Smolka Law Group, is essential.
Custody modifications are not granted lightly. Courts prefer stability and consistency for children, and a parent seeking to change an existing order must show a significant change in circumstances that affects the child’s welfare. Common grounds for seeking a modification include several different situations, detailed below.
One of the most common and contentious reasons for seeking a modification of child custody is the relocation of a parent. When a custodial parent plans to move a significant distance, it can drastically alter the existing parenting plan and affect the noncustodial parent's ability to maintain a meaningful relationship with the child.
Because such a move can disrupt the child’s routine, emotional stability, and support network, courts carefully scrutinize these cases to determine whether the relocation is truly in the child’s best interests. Courts will consider several critical factors when evaluating a proposed relocation, including:
The reason for the move
The impact on the child's relationship with the noncustodial parent
The feasibility of maintaining visitation
Whether the move serves the child’s best interests
Relocation cases are among the most contested and complicated types of custody modifications due to the high stakes involved. Because of this, courts approach relocation requests with caution and often require strong justification and detailed plans to preserve the child’s relationship with both parents.
A drastic change in a parent’s living environment can prompt a reevaluation of custody. If the new situation poses a threat to the child’s safety or stability, courts may modify the existing order. Judges will closely examine whether the current environment fosters a healthy, secure, and supportive atmosphere for the child.
If one parent develops a substance abuse problem or becomes involved in criminal activity, the other parent may petition for a modification to protect the child from potential harm. Evidence such as police reports, medical records, or drug test results may be necessary. Courts prioritize the child's safety and may impose supervised visitation or revoke custody rights altogether.
As children mature, their preferences may carry more weight in custody decisions. While not the sole determining factor, a court may consider a child’s wishes if they are expressed voluntarily and align with their best interests. The child’s age, maturity level, and reasoning behind the preference will all influence how much weight the court gives to their input.
If a parent’s job changes significantly, it may impact their ability to care for the child. Courts may adjust the custody schedule to accommodate the new work routine and preserve the child’s consistency. The goal is to make sure the child’s daily routine and emotional support system remain stable despite the parent’s altered availability.
A parent who consistently violates a custody agreement, such as by withholding visitation, not returning the child on time, or making unilateral decisions, may prompt the court to reconsider the custody arrangements. Repeated violations signal to the court that the parent may not be acting in the child’s best interests, which can justify a change in the order.
Child support orders are based on both parents’ incomes and the financial needs of the child. Over time, changes in either parent’s financial situation or the child’s needs may justify a modification. Because child support is intended to ensure the child's well-being, courts remain open to revisiting these orders when significant life changes occur.
A significant increase or decrease in income is one of the most common reasons to modify child support. Since child support is calculated using both parents' financial resources, even one parent's shift in income can create a material imbalance that requires court intervention. This could include the following situations:
A parent loses their job or takes a lower-paying position
A parent receives a substantial raise, bonus, or inheritance
A parent becomes disabled and unable to work
Courts generally require the change to be involuntary and substantial. Quitting a job to avoid paying support usually won’t qualify. Judges will closely examine financial records, employment history, and the reason for the change. Ultimately, any modification must make sure that the child continues to receive adequate financial support.
If the custody arrangement changes—for example, if the noncustodial parent gains more overnight visits or becomes the primary custodian—the support order may need to be recalculated. More time with a child can reduce the paying parent’s financial obligation. Courts strive to ensure that child support accurately reflects the actual division of parenting responsibilities.
As children grow, their needs evolve. Increased medical expenses, educational costs, or therapy needs may justify a higher support amount. Conversely, if a child’s expenses decrease, the court may reduce support. Any request for modification must clearly demonstrate how the child’s financial requirements have materially changed.
If a parent or child develops a serious illness or disability that affects income or requires additional expenses, this may be grounds for modification. Medical documentation will be crucial in these cases. Courts will also consider the long-term impact of the health condition on the parent’s earning capacity and the child’s care needs.
Whether you’re seeking to modify a child custody arrangement or a child support order, the process must be handled through the court system to become legally enforceable. Informal agreements between parents are not legally binding and may not be recognized by the court if disputes arise. Here are the typical steps involved in requesting a modification:
File a motion with the court: You must file a formal motion or petition with the family court explaining the specific changes you’re requesting and the substantial reasons behind them. Supporting documentation should be included to strengthen your case.
Serve the other parent: A legal notice must be given to the other parent, which includes serving them with a copy of your motion. This makes sure they have an opportunity to review your request and prepare a response.
Attend a hearing: Both parties will have the chance to present evidence and testimony at a court hearing. The judge will assess whether a substantial change in circumstances has occurred and whether the proposed modification is in the child’s best interests.
Receive a new order: If the judge approves the request, the court will issue a modified custody or support order. This new order replaces the previous one and becomes legally binding.
It’s important to note that the original court order remains in full effect until the judge approves the modification. This means you must continue to comply with all terms, whether related to visitation schedules or child support payments, until the court officially changes them. Acting outside of the existing order without court approval can result in legal penalties.
Life is full of unexpected changes, and custody or support orders may need to be adjusted over time to reflect a family’s new situation. If you believe your current arrangement no longer meets your child’s needs, modifying the existing court order may be the right step.
With an office in Palatine, Illinois, our family law attorneys serve clients throughout the Greater Chicago area. Contact our firm today to speak with one of our attorneys at Smolka Law Group.