Common sense is required and you should be fine:
Never deprive your child of food or water.
Don't use the elements (ie heat, cold, etc) as punishment.
Using corporal punishment is generally going to be frowned upon in most circles, but if you go that route, you should never ever leave a mark and it should be done when your temper is under control. Usually one swat on the bottom is all that would be necessary and the age of your child should be considered.
I think the most effective punishments are when you take something your child enjoys away from them for a period of time, like a toy or privilege, or when they get older, driving abilities, etc. For younger children, quite time outs for age appropriate periods of time are useful.
Long story short, there are no laws. CPS has been known to both overreact and underreact. The best policy is to just use your common sense as a parent. CPS won't likely get involved unless your children are showing up to school with bruises and or look malnourished or dehydrated. If you are in a contested custody suit, I always suggest using the mildest punishment possible just so opposing party has no grounds for accusations of abuse.
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