check valve?

It appears that I have a normally closed check valve installed in my house on the main sewer line. Most of the recommendations I've seen are calling for a normally open backwater valve to be used. In one article it even says the following: Installation of a check valve on your home’s main...

Hi Guys, Hey, I’m new to this forum. I stink at plumbing so please be kind! I’m handy but I don’t do roofs, electric and plumbing. I always run into trouble with plumbing so I always hire licensed and insured plumbers. Yesterday, my guy installed new sink and faucet (specifically a Kraus...