How long does Depakote take to work?

Are you taking it for mania?
If so this sight may be useful. http://blogs.psychcentral.com/bipolar/2008/08/bipolar-medication-spotlight-depakote-valproic-acid/
It is difficult to predict how long it will take for you to feel benefits from Depakote. Therapeutic levels of Depakote need to be reached in your blood.
When taking Depakote you need to maintain blood levels at a therapeutic level below the level of toxicity. If your Depakote level dips below its therapeutic level, the drug may become less effective. If it rises too high, the drug can become toxic, causing possible damage to the pancreas or liver. Always follow your dosage instructions.