Howdy all, new user/first post.Obligatory information:

House bought in 2018, built ~1990. Two story with open basement, on a well with septic tank. The water in this county is utter crap, super high amounts of gypsum, some iron, sulphur and almost the EPA max for TDS.

All plumbing is exposed in the basement so I have great access to three clean outs and can see the entire run including collector and exit from basement to septic tank. This summer I had the septic tank pumped.. but found about a foot of sand in the bottom. Turns out the concrete was almost completely corroded by gases so boom.. new tank and drain field. I had the guys put a ground level tank cap on as well as a drain field access pipe to deal with tree roots in the future. Both of these features have caps on them (obviously). But ever since the new tank happened the yard smells of poop. There is no odor inside the house so no concern there.. but the yard is a different story.
Here's the super weird part.. there is no odor on the septic side of the house. Like you'd expect the tank cap or that drainfield access pipe to be leaking smellies. Nope. Not a thing. All the stink is on the opposite side of the house.
There is a single roof vent that I'm expecting is tied to the upstairs toilet/shower and since it's on that 'side' of the roof line I'm betting that is the source. I mean, there legit is no other source.. period. So two questions to you fine folks:
A. Thoughts?
B. Can you have a cheater vent on a roof vent pipe?

no, you may NOT have an AAV (cheater vent) on a roof termination


AAVs are one way only inlet 'valves' designed to break trap siphonage


roof terminations are there to let air/gasses OUT to prevent 'air binding' as well as, occasionally, in

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

i'm surprised the septic people didn't recommend a filter for the vent stack

lots of differnt types and styles out there.

[www.google.com]

Thanks for the tip! Any ideas why we are experiencing the odors now and not the previous two years we lived here? I mean.. prevailing winds didn't up and change direction so it's baffling. And septic guys didn't touch anything indoors.. so it must have been venting then too. Unless maybe I don't have a good established bacteria and maybe the lack of sewer-eating microbes means stinkier gases?

Super interesting about the filter.. but this pipe is not nothing I can really even reach by myself. Or on some maintenance schedule as I'm sure those filter materials don't last forever right?



Edited 1 times.

correct

the filter material is activated carbon and requires replacement or 'regeneration'




you could try extending the roof termination up a few feet, but, that may require 'guy wires' to stabilize pipe

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Hmm, instead of extending what about a bend. Or, crap Im struggling to come up with other ideas here. I mean if this is really our new normal is a turd smelling yard then I'll have to do something to divert or stifle those fumes or we'd never be able to sell.

you could try extending the vent a couple of feet and the add a candy cane on top.

it may or may not help??

IMO:

a return bend will have NO - ZERO - NADA effect on any odors

the HEIGHT could have a marked effect as some roofs create 'dead spots' re: air circulation

assuming pvc piping: glue on a coupling leaving the top unglued (for test purposes) and insert as long a piece as you think safe (you want at least 7' total above roof), hopefully placing end ABOVE peak of roof


if this is a fix, you can reroute the vent inside the 'attic' to a point high enough that a shorter section will protrude ABOVE THE PEAK

BUT you need enough height so that the vent can not be blocked by an expected snow accumulation

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Good ideas, and I get the science behind it but this guy is already above peak. I'll try to get a pic when it's daylight, but yeah it's definitely not being sheltered from wind in any fashion.

Let me ask a dumb question.. So to try to paint the picture here our driveway is routed alongside the side of the house that the wellhead and the roof vent is on. The opposite side of the driveway there is an old satellite dish pole that I buried romex to this summer for a light. The channel we dug was sadly not below frost line, around a foot deep. The run from the house is ~50ft so I honestly wasn't too concerned. Anyway, during the digging we encountered some concrete at the edge of the driveway. I also got snagged on a ground rod that was under ground level. Ground rod and mystery concrete were within 2 feet of each other.
Now I did not break through the concrete, nor did I discover any edges or seams on it. Later on, thinking back my firs thought was it's a forgotten septic tank. And I've breached it's seal somehow. Except that shouldn't be plausible for a couple reasons.

A: The county has records of septic tanks going back to at least the 70's typically from what I understand.
B: We've had REALLY heavy vehicles that'll driven right across this unknown concrete. The excavator, dump truck and crane truck for the septic tank replacement work among the biggest.

Surely if I had a buried void right under my driveway..less than a foot deep no less, one of those vehicles would have discovered it in a bad way. But the smell, and septic work kinda coincided with me burying that romex so, I hope this helps describe my level of confusion on the cause.

I would think an abandodned septic would at least be filled with dirt. in any case itshould not smell after 30 years

>I would think an abandodned septic would at least be filled with dirt. in any case itshould not smell after 30 years

Unless it was not abandoned. About three years ago at a neighbor's home, a construction vehicle broke a previously unknown sewer line. At some time in the past, when a new septic field was installed, the previous owner had simply run a pipe from the old distribution box to a new distribution box to avoid having to replace the sewer main out of the house. Since the two distribution boxes were on different sides of the house, this was completely unexpected.

Advice to the OP: Find someone with a really good sense of smell (usually young and/or female) and ask them to sniff around all of these various locations outdoors.

Yeah I was hoping there was a more.. idk scientific maybe? Method of finding what stinks but, lol, I guess you are right. Need a person or a device with a great sniffer!

>>Yeah I was hoping there was a more.. idk scientific maybe? Method of finding what stinks


You could rent a smoke blower:

[www.youtube.com]
[www.youtube.com]

This place will ship one:

[rentaltoolsonline.com]

Not a plumber, but have owned a house on a septic system for over 20 yrs. I've noticed both times that I pumped the system out that for a few weeks I would get sewer smells periodically. I think the problem is from the recent pump out of the system. You depleted the bacteria that breaks down the waste. You might also at the same time be putting more water and or cleaning agents (like chlorine or oxygen bleach form the laundry) into the system then it can handle with the reduced bacteria load. Try adding septic system boosters and cut back on cleaning chemicals until you notice the smell is gone. After the bacteria is up to full strength the system should be able to handle periodic bleaches.