A: Hi, Frank, and thanks for being a loyal reader! First, please stop pouring bleach down your drains. In my opinion it's never a good idea, especially if you have a septic tank. Septic systems thrive on organisms that keep the system composting, and bleach may disrupt the cycle. We all need to think about what we pour down our drains to protect the environment in general.

Also, I have a feeling that you may just be resealing the fixture trap-water level with the bleach. Water may do the same thing to stop the bad gas odors. Let me explain: All plumbing fixtures should have U-shaped traps built in or just below the fixtures to trap water. The water plug in each fixture trap acts as a seal to stop sewer gasses from coming into the home.

Now, if the water level in the trap drops to a low level for some reason, sewer gases may enter the dwelling until the trap is resealed. What may cause a trap to fail? Most of the time, it's a seldom-used plumbing fixture (like a guest shower or sink) where the trap water simply evaporates. Refilling the trap with some water should fix this problem and running the water in the fixture at least once a month should maintain the trap seal.

Broken or leaking traps can also account for low water levels. In that case, the fixture trap needs to be repaired or — better yet — replaced. Toilets have a built-in trap, and if that internal trap ever cracks and/or leaks, unfortunately the toilet will have to be replaced.

Clogged and/or broken plumbing system vents or a lack of any plumbing vents at all also can account for odors and water being sucked out of traps. If this is the case, the vents may need to be serviced or replaced to correct the problem.

Finally, and I have seen this first hand, a careless plumber may have forgotten to install a trap at the fixture, and a new trap will have to be installed.

We can suspect the traps, but with all plumbing systems, odors may be tricky to locate and can emit from an area you never expected. So, don't put up a stink with me if the smell ends up coming from somewhere else!