2 sink problems: smell and noise?

Question

bought a house in may of 2006 and i'm working my way through the problems.

the kitchen sink when turned on full blast "chugs" or "knocks". the water comes out steady, but it sounds like it's trying to break lose a clog or something. it's a really weird noise to try and describe. it's always worked fine and to the best of my knowledge, there's no leak or anything. happens with hot or cold water.

the 2nd problem is a smell. doesn't happen all the time, but when it does, it smells EXACTLY like the rat cage we have downstairs. we have pet rats and the smell is identical. we've never cleaned the cage in the sink or flushed anything rat-related (not even their water) down the stink. the rats and anything rat-like have never been near the sink, period. what could be causing this smell? it doesn't happen all the time, but after you have the water on for more than 5 mins. or so (when doing dishes), you'll start to notice it a little. the smell comes from nowhere else but the sink.

Answer 1

The chug or knock is called a water hammer and is caused by air in the pipes. If it keeps happening, it means air keeps getting into the water pipes at some point, though not always from a leak. A water hammer can cause leaks from stress or rarely even break a pipe joint. The water hammer symptom is probably related to the smell.

Modern plumbing systems use water filled U-shaped pipe sections (look under your kitchen sink) as traps to prevent air (and noxious smells) from coming back up the drain. As long as the traps are full of water they block air and odors. If a water hammer or other system fault leaves an air gap, you'll smell your drainpipes.

Your plumbing will also have one or more outside vents (usually on the roof) to keep everything flowing smoothly - the air has to go somewhere to make room for the water. Either you have vent blockage or something was installed incorrectly. (recently replaced disposal in kitchen?)

You could get some do it yourself books from the library, but a plumber can likely diagnose and repair the problem faster.

Answer 2

The reason why your getting the smell is because when you run the water there is a vaccume that is sucking all the water out of the trap under your sink.

What you need to do is go outside of your house and identify the vent on your roof that is connected to your kitchen sink. From there, get a garden hose and run water down the stack and it should correct the problem.

As far as the air in your pipes, do you by any chance have well water? My Grandmother used to have well water and her sinks did the same thing. She upgraded to City water and the problem stopped!

Answer 3

Smell: Take apart the trap ((u-shaped pipe) beneath your sink and clean it out, as this is where smells usually reside. If you're not handy and there is no obvious standing water in the sink. put a few teaspoons of Dawn Concentrated dishwashing detergent, boil a big pot of hot water and pour it down at a steady rate. It will activate the dish soap and take all stinkification with it. Noise: Listen to the other guy about air in your pipes.

Answer 4

First you might have air in the water lines from repairs that where done, let the water run for a minute or two. (all faucets)

Sounds like a trap problem. make sure the trap is not leaking. (if you can)