It only takes about 15 minutes to get your California State Smog Check and you'll be good to move on down the road in your non-polluting ride. Congratulations, you're street legal. At Napa Smog Test Only in Napa, CA, we test cars, mini vans, SUVs and trucks for the DMV. We're open on Saturdays and should you need a STAR Certified Test, we can do that too, for an extra cost. Print our smog check coupon and save today. Se Habla Espanol.