<p>I brought this up a couple of years ago, and then forgot my own advice.</p>
<p>If your empty nest involves unused bathrooms, please flush and run water in the tub/shower weekly.
I relied on my husband who scrubbed and flushed the upstairs toilets since the study was on that level.
Turns out you have to also run water in the showers. The sewer gas smell nearly gagged me when I went upstairs today… The shower trap must have dried out enough to let gas through.
If you have an empty nest, run the shower / tub every week or so to keep water in the trap.</p>
<p>The point of having water in the trap to prevent the encroachment of sewer gases is valid but I don’t think most traps would dry out within a week. You could probably get away with doing it monthly or even less frequently.</p>
<p>It doesn’t take a lot of water to fill a trap - just a quart or so should do it.</p>
<p>Really??? Who knew. So if one has a shower that is rarely used, one should nevertheless turn it on from time to time. Huh. I had no idea. That’s not something my mamma taught me.</p>
<p>The only thing between your air and the sewer air and gases (including methane) is the water in the traps (at each sink, shower/tub, toilet, etc.). You may have been wondering why the pipes under the sink have that funny U shape in them where they dip down and up for a few inches before heading out to the drain. This is done purposely to trap water in it to block a path for the sewer gases to flow up from the sewer into your house.</p>
<p>It’s normally not a problem since they almost always contain water but if the particular drain goes unused for a long time the water in the trap can evaporate and the seal gone allowing gases in. ‘dragonmom’ pointed out that with the kids gone to college or elsewhere, there may be some bathrooms/showers that are now going unused for an extended time. It’s a good point. This is also an issue in some houses that simply have extra bathrooms/sinks/etc. that don’t get used much.</p>
<p>^^ Either one will do the same thing in this regard. If you don’t want to splash water around then just pour some water in the drain every now and then - maybe a quart or two.</p>
<p>^^ It’s the same thing with a septic system. The ‘wastes’ in the septic tank are broken down by bacteria and produce noxious gases.</p>
<p>I’m sure you’ve noticed the obnoxious smell when they’re cleaning out the septic tank - you don’t want those coming up through the pipes into the house.</p>
<p>Good advice! We also have a drain in our laundry room that would only get actual water in it if there was an overflow incident with the washer. So we periodically pour water down that drain to prevent just what you describe. I had not thought about running the upstairs shower every so often, though.</p>
<p>Interesting- now I know why our guest shower smells about once a year in the spring - I throw a little shampoo and turn the shower on to get rid of the smell.</p>
<p>Ok, GGD, you are right about not needing it weekly. We counted back and this shower hadn’t been used since about Easter. Not wanting to splash water all over the glass, I took the hand-held shower head off the hook and held it right over the drain before I turned it on.
Pouring water from a pitcher would have worked also.<br>
DH wanted to consider putting plastic over the drain so water wouldn’t evaporate. Hmmm, but it will still evaporate from the vent stack which opens on the roof, so it could still dry out enough to be a problem.</p>
<p>^^ You’re right on the evaporating out the vent stack (you know your plumbing!) but covering the drain might decrease the evaporation somewhat as well but I wouldn’t bother with it - it’s easier to just pour some water in (or turn on the faucet) every now and then and that way you’re sure it’s taken care of.</p>
<p>My new plan; first Saturday of the month ( unless I program my cell phone otherwise), I get an alert: new contact lenses, flush toilets and run a bit in showers upstairs, weed the back beds, get a pedicure.<br>
See, adding a reward makes me remember…</p>
<p>GGD - yes, I know my plumbing. DH and I watched the first season of This Old House as newlyweds. Back when they showed how to do stuff. Thirty something seasons later we’re still hooked. We just love houses…</p>
<p>You don’t have to do it weekly, but I don’t know how long it takes. We have a basement bathroom that almost never gets used and the toilet dried out once and smelled horrible. It doesn’t take much water since all you have to do is get a few inches in the trap.</p>
<p>Wow, thank you so much for this info. Very relevant since we’ve moved and are about to put the old house on the market and it’s empty most of the time. It has a lot of bathrooms and sinks and while I’ve been turning the taps off under the sinks it never occurred to me that running water into the u bends would be important. Yet another potential home-selling disaster can be averted!</p>