The North Carolina Building Code requires you to have a backwater valve if your plumbing fixtures are below the top of the first, upstream manhole on your street. A properly operating backwater valve allows flow to only go in one direction, thus preventing wastewater from entering your building during regular sewer system maintenance or inadvertent sewer system backups. To find out if you have or need a backwater valve, check your plumbing plans or consult with your builder or professional plumber. If sewage backs up into your home, the cost to repair damages and clean up the mess may be high, and towns cannot be held liable for damages when a backwater valve has not been installed by a property owner.
Do you need a backwater valve?