I have a double kitchen sink. What is the correct way to install drain? There is no disposal or dishwasher involved. I see double kitchen sinks installed with two p-traps in drain configuration and some with only one p-trap, which way is correct?
Also I have a double kitchen sink with two p-traps installed in drain, when running water into one of the sides of sink ,water will back-up into the other side of sink. Is this due to slow running drain (main drain in wall) or due to drain configuration?
Are there check valves for drain pipes?