The Basics of Sewer Backflow Preventer

By | November 11, 2016

Sewer backflow preventer, commonly referred to as sewer backwater valves prevent raw sewage from backing up into your home through the toilets, showers and other parts of the house.  Similar to the concept of irrigation backflow preventers used in lawn sprinkler systems, sewer backwater valves deal with creating a sort of a one-way floodgate to resist the backwards flow of liquids.

sewer backflow preventer

How does sewer backflow happen?

Incidents of sewer backflow happen when the city’s main sewer lines become clogged without people realizing it. As people have no knowledge of the clogging in the sewer lines, they will just go about their normal business of flushing toilets and using the taps. With constant water flow while the lines being clogged, water will just flow to any empty space until it overflows the sewage and flood the basement.These could result in a number of problems and damages to your property, not to mention the potential hazards overflown sewage pose.

If you have one already installed, Sewer backflow preventer like backwater valves automatically close if sewage backs up from the main sewer – thereby saving you from the possible damage.

Sewer backflow preventer installation basics

If you are considering to install a sewer backflow preventer for your home, you must first take into account a number of things. First, make sure that you get all the necessary permit from your municipal government and find out what type of equipment they require or recommend. Next, check that your foundation drain and eaves trough downspouts are not connected to the weeping tile and sanitary sewer. It would also be wise to hire a licensed plumber to install a mainline backwater valve as well as to acquire the necessary building permits. After these and when the eaves troughs have been disconnected from the sewer system, they should be drained in a way that it does not direct water to neighboring properties.

How much does a sewer backflow preventer installation cost?

Depending on the type of a sewer backflow preventer you are going to put, installation costs and the cost of the actual device may vary. As per FEMA, the average cost for hiring a licensed plumber or contractor to install the device is approximately $1,400 for a combined gate/flap valve or about $600 for a flap valve. The estimated figure includes the cost of excavation and backfilling.

Other sources, however, estimate the initial construction ranging from $150 to $250. While the retrofitting could range from $1000 to $2000 as some concrete are to be removed to gain access to the sewer line.

Advantage of installing a sewer backflow preventer

Serving as a one-way gate for your sewage, having a sewer line backflow preventer installed could come in handy especially if you are living in a flood prone area. The cost of installation including labor is a good enough investment considering the economic damage and personal inconvenience an overflown sewer line could cause.Accordingly, most municipalities in the United States require the installation of these safety devices in both residential and commercial buildings.