sandman,

Very little to go on. Do you know which wall is the plumbing wall? Is that where the sound comes from? What makes you think the sound is caused by the water meter? Is it more of a rapid banging or rattling sound versus a pumping sound(describe a pumping sound in more detail)? Do you have a pressure regulator on your house water system? It's usually in the garage. Does your irrigation system come off a house hose faucet or connected directly from your outside water main. Water meters are not usually in the house but out by the curb in the City Right-of-Way so it can be read by the water meter company. What did the water company say they thought caused the noise? More details please. Aloha