My backflow inhibitor

Last week I was excited to see a city crew with a backhoe ready to dig up my front yard. At long last I was getting a backflow inhibitor on my sewer line.

 Last fall I noticed similar activity at a neighbor's house and asked what was going on. I learned that the city would install a device on a sewer line to prevent sewage backup into the basement when Rensselaer has extremely heavy rains. Further, the installation was free to the homeowner. (It turned out I had to pay a bit because of a complication explained below.) I put my name on the list and waited.

Early this year the city put flags on my lawn marking where the gas and electric lines were. Then about a month ago several guys came to the house with equipment to locate the sewer line. They put a long snake with a metal head into the sewer but they could not get past the the wall. They were quite sure that the line took a 90 degree turn there. They told me that I would have to have Roto-Rooter come in to find the line. Roto-Rooter has better equipment that can go where the city equipment does not go.

I called RotoRooter and a few days later they came. They scoped out my drain. The picture below shows where my sewer line drops down to connect to the city sewer. The main guy was rather surprised to see that my sewer line was cast iron the whole way. He said that with World War I the cast iron sewer lines were usually abandoned for tile. However, my house was built several years before WWI.

 It was cold on the day the city arrived, so I only watched bits and pieces. I was surprised that they brought in the big truck.

 Below is the device that they installed. They cut out a section of the cast iron pipe and replaced it with a section of plastic. The white part is the part with the valve. I saw the inside but did not get a picture of it. However, I did find a picture of what is inside on the Internet: see here and scroll down. The device is very simple. There is a thin, black plastic flap that is held in place with a simple hinge. Water can lift the hinge and go out, but water coming back will close push the plastic flap closed.

 The Roto Rooter guy told me that the drain was seven feet deep where it connected to the city sewer. That is what the crew found. You can see the top of head of one of the workers in the picture below--he is standing up.

 The crew filled the hole but left a tube down to the value just in case some maintenance needs to be done. They told me that if I ever have Roto Rooter back, I should tell them that there is backflow inhibitor on the line because if their probe goes past it, it might not be easy bringing it back.

Cities that do not have have combined storm and sewer systems do not face this problem. The city will soon be installing a facility on Lincoln Avenue to deal with the sewer system being overwhelmed in heavy rains, but the main purpose of that will not be to protect basements but rather to protect the river.