PLUMBING Certified Backflow Checks Mapleservice is your source for certifying backflow prevention devices. Most Northern California water agencies and districts require that commercial and health-care facilities install backflow prevention devices. These devices prevent water back-flowing into the public system(s). Most water agencies also require that backflow prevention devices be tested periodically. The testing frequency are normally from every 1 to 5 years. Any testing/certifying entity must be certified for testing. Mapleservice is certified by the “American Water Works Association” for all backflow prevention testing. Our certification number is 07388. Back to the top of the page • Main page • Home • E-mail Us Content from this site may not be reused without permission.