My main water shutoff won't shut off. Everyone I talk too says replace the gate valve with a ball valve. The plumber where I work says use Shark Bite fittings as they are quick and easy. I looked them up and I think this is what I will use. They also recommend that while I'm at it I go ahead and change out my water pressure valve. The one's I see have a factory setting of 45 PSI. Is this what's normal for residential?