I had a really strong sewage smell coming from a bathroom yesterday after a heavy rain for about an hour. It smelled up the entire house. I had my septic tank pumped and had new field lines put in a few weeks back. Since this has never happened before i assumed that was the issue. I called the guy who installed the lines and he said that if water was draining (which it was) then the field lines were not the issue. He said I needed to replace the wax seal on my toilet in the bathroom where the smell was coming from. I replaced the wax seal yesterday but by then the smell was subsiding (a few hours after the rain stopped). All was well then more rain that afternoon and the smell came back but this time it was coming from the kitchen. It was really strong for a few hours and it slowly went away an hour our so after the rain stopped.

This morning I got on my roof and checked my vent pipes, (1) 3" pipe and (1) 2" pipe, thinking that maybe one or both were stopped up. The 3" pipe went straight to the ground and it looked clear. The 2" pipe had a bend a few feet down so I couldn't see to the bottom. I took a garden hose with a jet nozzle and ran down the pipes blasting water. I let it run for about 5 min. in each pipe. Everything seemed to drain fine so they seem clear. Although its possible the 2" pipe could have been clogged after the bend and the water cleared it out but there is no way to tell. After running all that water in the vent pipes there is no smell. Do you think this fixed this issue? Is there something else I could check? Do you think it has anything to do with the new field lines? I've lived in this house for 18 years and never had this happens. It seems like an odd coincidence that this would happen after the field line install and that has nothing to do with it. Thanks for any advice that you can give.

 

What type of septic system do you have?

Is there any chance the smell was coming from outside and got blown into the house?

 

I guess its just a standard septic system. It has a concrete septic tank and they installed those graveless field lines that have the open bottom. My old lines were the perforated 4" flexible drain pipes in gravel. No smell from the outside. The 1st time it was defiantly coming from the bathroom. The whole house smelled bad but it was way worse in the bathroom. After replacing the wax seal in the bathroom I guess it directed the gasses to our kitchen when it rained the 2nd time.

 

I don't see how odors could be coming from the drains if your plumbing system has the proper traps at each sink and shower and the system is properly vented. I remember way back after a friend had purchased an older house in a very rural area that there was a sewage smell that came from the washing machine standpipe. Turned out there was no trap at all in the crawl space for the washer.

 

I agree but it has proper traps. I'm stumped at this point but I'm no plumber. Like I've said, I have lived here for 18 years and never had this issue. Get new field lines and this happens. Could that have anything to do with it? I cant think of any but it seems like a weird coincidence.

 

How far are your bathroom and kitchen from each other? Is there crawl space or unfinished basement below the area where you could go inspect the piping when you are having the smell?

 

There is about 15' between the bathroom and the kitchen. I have a crawl space. I went under the house right after the 1st rain and did not smell anything. You could only smell it inside the house.

 

Do you know if your house has a whole-house trap? It's usually a U-trap inside the house/crawlspace just before the sewer line goes outside. Houses with septic around here all have them, but I do believe it's a regional thing.

It sounds like you know the traps hold water to keep sewer gasses out. It is strange that you'd have two trap issues (wax ring and something in the kitchen), but maybe your new septic system is allowing some back-drafting that the old one didn't - and is highlighting issues you've had all along but never realized. The wax ring makes sense, and maybe your kitchen sink isn't vented correctly and its trap is being sucked dry.
Next time it happens, check to see if the water level in the kitchen trap looks reasonable (if you can see it), or see if turning on the faucet for a cup or two worth of water helps.

 

When I read septic/rain/odor I said hmm that sounds like us 4 years ago. We live in Mexico and I'm sure no one in the US has seen a septic system quite like ours. When we are in the rainy season it rains hard every night. The ground gets saturated (walls fall etc). For several years when the rains came our master bath started to smell. Plumber after plumber would say the problem was the drains in the floor, which I guess are like traps in the US. Finally I had enough and dug up the lines leading to the tanks (which was hard because the plans for the house were useless). After a lot of digging it turns out someone used the cheapest grade 4" PVC (like 20 years ago) and the tube was crushed halfway to the tanks - right near a very happy huge Avacado tree. So in reality - although the odors came with the rains the system was never working correctly. When the ground was saturated the waste couldn't leave even the crushed pipe. We have two large (1100 liter) tanks that sit in front of our leach field/drainage ditch. When we opened the first tank it was 'stagnant'. So now I have a tee cap near the wall to the house and this year when opened the tank for pumping I stuck a garden house in the tee and made sure that the water was reaching the tank. All was good but to be honest I know that there are at least 2 more 4" tubes that lead to the septic tanks from the other side of the house and I have done nothing with them (yet) because we no longer have odors in the house.

 

Thanks for the replys. Im not sure about the U-trap right before it exists the house. Ill have to check that one. The bathroom is 1st in line from the tank so i guess that was the closest spot for the gases to come out. Once I fixed that Im guessing that it went to the next spot witch was my kitchen. Just not sure why it didn't go out the vent pipes since they both seemed clear. I will say my plumbing under my kitchen sink is a rats nest and may not be air tight. I may rip it out this weekend and redo just in case. Still not sure why it did this now when nothing has changed except the field lines.

 

Got an update. We have received a lot of rain over the last 24 hours and no smell. I'm still not sure what the cause was or maybe flushing out the vents did something even though I didn't see a clog. Thanks for the advice.