Continuity mistake: When Chet and Marco are hosing the gas meter fire, they are both wearing gloves while handling the hoses. However, after Roy helps Chet up from his stumble, there is a closeup of the hoses and it's a bare hand handling the hose.
Continuity mistake: Just after Brackett tells Early that the patient he was talking to is his father, it cuts to a shot of Squad 51 pulling up the driveway, and the Engine 51 we see parked in the apparatus bay is not the current Ward LaFrance pumper, it's the original Crown engine from seasons 1 and 2.
Answer: It is standard practice to wet down driveways so that they stand out in a long shot.
stiiggy