It seems the trap was left out on the shower drain on a slab house. Any way to fix that short of a jack hammer?
Mychief
| Posted in GBA Pro Help on
My son just moved into a slab house on a septic system. After using the washing machine, they noticed a sewer smell coming from the shower drain. They had showered the day before. If there is indeed no trap between the shower and the septic tank, is there a solution short of a jack hammer? Perhaps a valve? The drain is a trough style with a 1.5 inch opening.
I told him that maybe the washing machine had emptied the trap. There is a vent for the washing machine and behind the shower.
Is there a simple way to tell if there is a trap? Thanks
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Replies
The trap for the shower needs to be by the shower. Have u confirmed there are no floor drains where the trap may have dried out? Have u run water at all fixtures to eliminate a dry trap?
You can use a sewer camera to check for a teal or try to "feel" the turn with a sewer snake. If I don't want to tear out concrete there are shower units available with elevated bases that allow a trap above the ff.
Tooger,
It's more likely the shower is lacking a vent, not a trap, or that the horizontal run has a configuration that siphons the trap.
Tooger,
The first image shows what you need to be feeling for when you are assessing what you have under your slab.
The second image shows the task ahead of you if you need to install a missing trap.
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I had a similar situation in my utility room. After using the washer, a strong sewer smell came from the floor drain. I was sure the trap was leaky or the vent stack was clogged and the trap was siphoning. I put in hours myself, and having plumbers inspect and clean out the vent and trap.
Neither was a problem. Instead the washer's internal and external drain hose had built up a thick biofilm that was producing the sewer small every time the washer ran. Microbes can flourish on soapy residue. Inspect your washer's drain hoses.
Good point, Phil. Any tips on cleaning that? Or is there no getting around the need to disassemble it and scrape/wipe the mess out?
It should be very easy to see if there's a trap there--remove the grille on top of the drain and look dowb with a flashlight. There should be water standing there, several inches down, and if you probe with a piece of wire there should be a "bottom" an inch or two below the waterline.
If there's no water, put some in and see if it stays. If it does, there's a trap and it has been siphoned dry. With the trap full, run the washing machine and watch what happens when it pumps out. If the water in the trap oscillates or just disappears, you have a venting problem.
i appreciate the thoughts. It is a new construction. We will check to make sure if a trap or not. If not, we are leaning toward making a bath tub drain stopper work. (one of those push to open, push to close.) We have not found a drain seal (like Grate Seal) made for a 1.5 inch drain. Again, thanks for the input.
Just a point about comparing the shower to the clothes washer: you can't. The piping rules (code) for clothes washers are different. Clothes washers pressurize the drainage of grey water outflow and the centre of the trap arm must be within a specified distance from the washer's outlet hose mouth, irrespective of the stand pipe elevation. That is why most washer traps are above the floor (to achieve the code specified spacing). Most of what you see on the internet etc about hose-to-trap arm spacing is confusing as it presumes hose-mouth-to-trap-arm distance is identical to stand-pipe-height-to-trap-arm. I have a clothes washer trap below the floor so I run the clothes washer hose about 30" feet down the stand pipe to achieve a 24" spacing to the trap arm.
The shower's trap on the other hand is normally in or below the floor, drainage works by gravity, and the trap cannot siphon if the trap arm is at least 4 inches long and a vent is close enough. I agree that the problem in the shower issue is probably the vent location (if ther is one at all) (depends on code, best to have it within five feet). No vent and you get a siphoning trap and a backing up/slowing of the outflow.
Just another point. If the house was left unoccupied for some time ( weekend can do it in a heated house, dry climate), the traps dry out on their own and that could explain the sewer smell. Regular use may restore the function of the trap. I would use it for a while before making any changes.
Missing traps or vents is code failure that makes the seller of the house, the private house inspector (if you used one), and the municipal building inspector who granted occupancy liable, by the way.
Flitch,
Perhaps your system is different, but our code clearly puts the responsibility for compliance on the owner, and indemnifies the permit issuer and their inspectors from anything short of deliberate negligence. All the private house inspection contracts i've seen similarly exclude hidden defects. The OP might have a case against the seller, but going after the inspectors would be a waste of time here.
Interesting discussion. Not sure if this is relevant for Tooger's situation but I'm sure it is for the topic of washing machine drainage. I'm getting ready to install an all in one condensing washer dryer to save space and eliminate unconditioned return air from a conventional hot air clothes dryer. As I was researching the unit I was interested in I looked up how people rated it and any problems with it. It turns out there was a significant problem with wet clothes when the unit's drainage hose was connected to a normal 3' or 4' standpipe. The solution in the remarks was to make the hose connection no higher that 10" or so above the floor. So that's what I've done as preliminary to ordering the unit.
This idea of a drain for the washer located no higher than 10" or so above the floor, (or at floor level) seems like a good idea to me, and probably should become standard. It would simultaneously allow lower drain water pumping pressure and move the end of the drain hose much closer to the trap. It might simultaneously remove some of the gunky buildup in drain hoses that can occur with washers needing to overcome the drainpipe height. Again, this might not have anything to do with Tooger's problem but is a related side issue.
Eric,
I'm pretty sure that violates your code. The high drain height (here I think it is 30") is to prevent back flow. The IRC has similar restrictions.
hmm... I'll have to check that. That makes sense but I hope you're wrong.
Back to the original question. Assume there is no trap. Could one use a tub push on/push off and adapt it? Or some other one way valve? Again, thanks.
Relying on a pop up drain is a terrible idea and probably wouldn't seal tight enough to prevent the sewer gas smell. Besides being unpleasant, having sewer gas in your house could potentially be dangerous depending on the severity.
You said this is a new house? Hold the builder accountable if the trap has truly been omitted!
I'm not sure it would be a good idea to be in the shower with no trap with the drain open. Sewer gases that came up would be in a small and perhaps partly enclosed shower stall, in a perhaps small bathroom with the door perhaps closed. That doesn't seem healthy to me, even if the smell is tolerable. Anyway, first step is to figure out whether there is a trap or not.
A late response to Charlie Sullivan (comment #5) - On my washer I had to take off the top, back, and front to get adequate access to the internal hose. I then pulled that internal drain hose all the way out to degunk it. I'll probably rig a bottle brush on a fish tape, or something similar next time.