How long do I need to wait before painting treated wood?

My husband always waits a year, just to be on the safe side. But he says depending on how dry the weather it could be six months. If you apply paint to the wood and the moisture is still in the wood it can cause the paint to bubble up and peel off.

I've never given "waiting to paint treated wood" much thought. Normally I will apply a good primer coat and then the top coat as soon as the carpentry is done. I suppose if the wood were unusually wet or if the weather wasn't conducive to painting I would hold off but If you wait too long... the wood starts to crack and warp because it's not protected from the elements.

There's No Clear Cut Time Here For This, Once The Lumber Has Been Treated And Arrives At The Lumber Yard Where You Buy It, There's No Telling How Long It Has Already Sat There, What I Do Is Just Take A Look At What It Looks Like, Is It Really Wet , Really Green, When You Touch It Does Some Come Off On Your Hands?? Unless Its Doing Any Of This, I Usually Prime And Paint It, Your All Right In The Fact If It Is Not Dry It Will Blister And Peel. But To Be Honest I Think Painting Treated Material Is A Bad Idea, Its Not Made For That, It Meant To Be Stained, If You Want A More Painted Than Stained Look You Can Get Stain That Has Solid Color.

Use a moisture meter to see how wet it is, then follow manufacturer's recommendations.

A stain is a better outdoor solution. An opaque stain will appear more like paint.

What type of sealer should be used when painting treated lumber?

I don't know of a sealer for painting treated, there is one for staining treated

Wait at least one year before painting treated lumber.