What can cause kitchen and bathroom drain problems?

You might begin by following your own advice: "If I may suggest, I think it is best that you consult a certified plumber to avoid costly mistakes"

We can help but we need more information . Please explain, in detail, what problems you are having. Blockage? Bad smells? Other? Back to you. Tom

Yes, more info please.

Judy, love that answer, but maybe marc has realized he is consulting certified plumbers when he comes to the plumbing page here.

Yes, I think that was brought to his attention - smiling.

What can cause kitchen and bathroom drain problems? We still need more details but to answer your question, Garbage and grease will clog a kitchen drain while rotting hair and grease mixed will clog bathroom drains, Is that what you want to know? Tom

While we are on the subject, how safe are drain cleaners, granules and liquid?

I'm always afraid to use them - although I've never had a pipe I couldn't "plunge" clear.

how safe are drain cleaners, granules and liquid?

As a repair plumber I have never recommended using harsh chemicals. In your drainage system. Besides they only seem to work in TV commercials and when you try to remove the water you could burn your hands or damage your eyes. Some years back I lost a good friend by using a sulfitic acid based product in a unventilated bath room. My own lungs are scared from using acid to boil lime out of toilets.

I agree with Tom. As plumbers, we steer clear of chems. If you can't unclog it with a plunger, its time to auger the drain.