The drawing above shows how a backwater valve works to protect your home from sewage backing up into your home
Installation of a backwater valve is an important step in preventing city sewage from backing up into your home. Sewage presents a significant and serious health hazard as well as a very large cleanup bill that your insurance company may or may not completely cover. It is important to you and to your insurance company that you take steps to minimize your risk of basement flooding due to sewage backup.
A backwater valve, when installed in the drain system below the floor allows water from your sinks, tubs and toilets to flow out of your home. However, when the city sewers become overwhelmed because of heavy rain or spring thaw, sewage begins to back up into the houses that have the least resistance. A backwater valve has a gate that closes when it detects a backup and prevents sewage from entering your home.
In most, if not all municipalities, a building permit is required to install a backwater valve and an inspection must be done before filling in the hole.
NOTE: In some cases a municipal government rebate is available to homeowners who install the backwater valve. NFPs Independent Service Provider (ISP) agrees to obtain permits and help you through all the paperwork to apply for a government rebate if it is accessible to you.
Once installed, the backwater valve can be monitored by the same system used for the Main Water Shutoff and if sewage backup is detected will automatically shut off your main water supply. The goal is to stop you from using your sinks, tubs and toilets. The closed backwater valve will not allow water to flow out of your home and unless the incoming water is shut off your in-home drains will quickly begin backing up and will flood your basement. The system shut-off will alert you to the fact that your home is at immediate risk of basement flooding and if your system is being monitored, we will know about it…probably before you do.