Customer called us out for a bad smell coming from kitchen sink when clothes washer is ran. On arrival she informed me that the utility sink in the laundry room had also started to back up today. I tested both the utility sink and the kitchen sink. The kitchen sink started to back up after about 5 minutes. I recommended clearing the line of any grease using a k-400 cable machine through the kitchen sink and using Endure to make sure it doesn’t happen again. Customer agreed. I removed the ptrap from the kitchen sink and ran the k-400 down the line successfully clearing the blockage. I tested the line by running the utility sink for bout 10 minutes and did not have any back ups. I reinstalled the ptrap for the kitchen sink and ran both the kitchen and utility sink for an additional 15 minutes while I cleaned up. Tested the p trap and had no leaks.