I'm in CA. I bought my house a while back. I have been examining different items in my house to make sure they meet code. My water heater is inside the house and has a b-vent attached to the WH hood and it goes through the ceiling into the attic. The b-vent extends about 1' 6" above the ceiling in the attic and is not near any combustibles. Then someone attached a 5' flexible b-vent and it turns up with two bends (no greater than a 45 bend) up through the roof jack. It is all locked together. I have been looking and looking for CA code on proper WH venting. Does it meet code to have flexible b-vent in the attic from the double wall b-vent and going through the roof or should be only be double wall b-vent all the way? I don't want to have any potential fire hazard in my attic. Thanks in advance!