Send Venmo Payments to (206) 409-7622 - "Please Add Invoice Number so We Can Make Sure to Credit Your Account." Pop's Backflow Testing Service is dedicated to keeping your drinking water safe. As a business, we understand that property owners want to have their backflow assemblies tested quickly, affordably, and without hassle by a reliable professional. As parents of young children, we understand the need for honesty, integrity, and old-fashioned manners in everything we do. Call Pop's right now and check one more thing off your list.