New baby - support mod?

[Lindma]

My husband and I just had a new baby. Does DSHS (WA state) adjust for this change, or do we have to file new paper work and jump through all the hoops in court to make the adjustment?
If anyone has any insight your input is greatly appreciated.

[Groundhogday]

Yes, you will need to file for a modification of the child support order due to the significant change in circumstances (new child in the family).

[Lindma]

Has anyone had to do this before?
Do you know if they make the support retroactive to the date you file for the mod?