The best time to water new sod is between 4 and 8 a.m.---when the wind is usually low and there's less evaporation. If you can't water during that period, anytime before noon will do. Midday watering isn't effective because most of the water evaporates. Waiting until the evening increases the likelihood of introducing disease.
Water new sod one or two times a day. You want the entire sod strip to be wet, and the soil beneath to be damp about 1 inch down. Overwatering can effect the health of the lawn, so make sure not to saturate the soil.
Check the moisture by picking up the corners of the sod. If the grass and soil are excessively wet, wait to water again. If they are dry, add more water.