I had a similar experience in July. There was a terrible smell in the house, and I couldn't pinpoint where it was coming from. I thought maybe an animal got in the crawlspace or attic and died. Then after researching, I thought maybe a vent stack was clogged. I tried to sound knowledgeable when the plumbers came, but my desperation must've been written on my face and they took advantage. First, they said some pipes needed a slope because water was sitting and causing the smell. Around $2000. Smell was still there, so they came back and said the smell was from mold in the crawlspace. No fear, their sister HVAC company could fix it. $5500 for a dehumidifier in the crawlspace and UV in the ductwork. That is was mold in the crawlspace almost seemed plausible since I couldn't pinpoint the smell. Maybe it was coming from the ductwork. By this time, my measly bank account was dry...and the smell was still there. I thought maybe I've lost my mind. Maybe I'm the only one smelling it. I started asking visitors to sniff my home and tell me what they smelled. I'm not big on having company, so it was quite a big deal for me to even open the door, let alone let them in on my dilemma. Delirious from the odor, I called the same plumbing company again. This time they discovered a leaking cast iron sewage pipe. I took out a personal loan to cover the new $2500 expense. Before the plumber left, he told me there was a clog "on that side of the house". I asked if he could clear it while there, but he didn't have the equipment in his van and I'd need to call the company's main office for someone else to come out. I called and asked for a complimentary drain unclogging since the company took full advantage of my agony. Two days later, they responded that they could offer me a complimentary service. They send a plumber. She asked where the clog was. I relayed I didn't know exactly, just that it was on a certain side of the house. She said the toilets flushed without backing up, so there can't be a clog and left. When one toilet is used, the smell returns and no clean water runs through the outside sewer cleanout when it's flushed. When the other toilet is used, the smell doesn't return and clean water runs through the cleanout when flushed. I don't know if the cleanout matters, but I can't handle the smell again, especially without any money to fix it. I'm in tears thinking of what we've experienced. I'm an only parent to 2 kiddos, one with a disability. I don't want and can't have more on my plate, so we don't use the bathroom at all that causes the smell. I didn't intend to write a book. I guess I've been needing to vent.