How much water should I put in the water pan, and how often should I check it?

Fill the water pan with warm water or marinade to 1 inch below the rim — a full pan holds 4 quarts (1 gallon) and will last 2-3 hours. Check the water level every 2 hours during cooking, and listen for a sizzling sound which may indicate the water level is low. Never allow all the water to evaporate while coals are burning, as grease can catch fire. (Page 2)