I'm amazed at all of the answers that seem incorrect to me. Utah State Law requires that EM deposits are to be deposited within 3 days. While the Utah State Approved REPC may have the Seller and Buyer agree to another number of days, the State Requires 3 days for the deposit unless otherwise agreed upon by the Seller and Buyer.
There are countless different Purchase Contracts that are used in the State of Utah. For example, almost every homebuilder has their own contract that they use. These different contracts may specify all sorts of different time frames for the depositing of Earnest Money.
So in short, Earnest Money is to be deposited within 3 days unless agreed upon differently by the Buyer and Seller.