When the non-custodial parent possesses rental properties, does that count towards net income when determining child support?

Net income for child support purposes includes income from all sources, including rental income. Temporary child support orders are always modifiable. If the order was entered within the last 30 days, file a petition to vacate and/or modify child support award. If you were represented by a lawyer, s/he should have requested/demanded that he provide proper documentation of all of his income, not just a few pay stubs. If you are not represented by a lawyer, you should hire one. You cannot afford not to be represented.

Child support is based upon a percentage of the obligor's net income from ALL sources, not just employment income.

Child support is based on net income- income from all sources. This does include rental properties. Yes there is motion to vacate and motion to modify support. I suggest counsel so they can help with discovery of those assets (and others for that matter).

Next time, make sure to get him to show his tax return. You have a right to see those. Generally, if there is a petition for modification, you can make him file a financial affidavit which lists all his assets and liabilities and income and expenses.

Contact your lawyer about a possible Motion to Vacate and/or Modify.