Column #859 08/13/11
On The Level
Q. My house pipes or something are "groaning" frequently and loudly. It seems to have started this past winter. I live in a 16 year old 3 story townhouse condo. The first floor is finished. The laundry, a powder room, living room, entry and garage are all on the first floor. The groaning seems to be coming from the first floor. You can almost feel a concurrent vibration. It lasts approximately 5 seconds. It occurs during waking hours when the house is being "lived in"-- doing laundry, dishes, flushing commodes, showering etc.This makes me think that it is related to my pipes and the water flow. Do you have any thoughts or ideas? I must admit that I am quite concerned and unsure of how to proceed.
A. There are a few things that make plumbing pipes noisy and the most common is something called water hammer, then there is a ticking sound that occurs with plastic waste lines called pipe growth and the rarest is what I think you have-- moaning. It is related to the venting system of the waste lines.
I was called to a mature neighborhood some years ago where my friends were hearing a loud moaning occurring mostly during the mornings in their master bath on the second floor. They asked me to come over and hear it for myself.
The first couple of times over to the house I heard nothing and my friends assured me they werenít crazy or making this up. The third time was a charm. It was fairly early in the morning and sitting in the kitchen it sounded like a distant fog horn. They werenít kidding. It was very loud up in the master bath and I could tell it was coming from DWV (drain, waste and vent) pipe. Thatís the main sewer line that vents out the roof and exits the house in the basement to the main sewer in the street. Down in the basement I could see that it was a four inch line that drained out through the front wall toward the street.
After listening for a while I came to the conclusion that probably a dip due to settlement had occurred out in the sewer main under the street and as the neighbors upstream showered and flushed during their morning routines, the main was filling and the dipped pipe under the street was becoming trap-like and using the DWV line of this house as a large vent creating the fog-horn like noise. I told the folks what I thought and told them to contact the relevant people who take care of sewers in that neighborhood and let them know.
They did and the department spokesperson told them I had taken leave of my senses and that couldnít be their problem. The problem persisted and about a week later my friends spotted some official looking types out in the street marking an area in the center with spray paint. A few days later digging equipment arrived. They dug up the main, adjusted it and the problem of the fog horn vent ceased.
Something along those lines is probably occurring at your house especially if the problem only recently-- relatively speaking-- presented itself. Most houses connected to municipal sewer systems have an access pipe out front near the property line. They usually stick up a few inches because when plumbers install them they are attached to the sewer line the front yard is all dug up with construction. They are making an educated guess as to where final grade will be and always err on the side of being a little too high. They donít want to have to be called back to extend it to grade because the municipal plumbing inspector wants to see it before signing off on the job. People call that a clean-out but itís really not. Itís there so should there be a back-up problem in the house the municipal guy can open it up to see if the problem is on your nickel or theirs. Itís usually on yours. Small children are inventive as to what they can stuff down a toilet which can and will create problems.
If you do nothing I can only imagine the noise will persist until somebody does something. You might consult with an experienced plumber to see if he can pin-point the cause if itís in the house or if it points to problems somewhere else. Since you say it occurs only when you are using the plumbing and doesnít spontaneously happen as it did in my friend's house suggests it could be just your system. Iíd do something because the worst case would be if the noise is signaling the beginning of a condition that could results in a blockage. Then youíve really got trouble.
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