On some days the unit smelled bad, like rotten eggs. The sewage from the shower drain backflowed into the shower basin, there was visible feces and other bits of sewage left behind. I informed the host and they came to clean the shower basin the next day.
Progressively the rotten eggs smell became worse and it comes and goes, at first I couldn't identify what the bad smell was until we would hear audible gurgles coming from the drain, throwing hydrogen sulfide aka sewer gas into the unit. The gas lingered because the bathroom is right beside the bedroom and during the night it caused me to feel nauseous and eyes to become irritated and watery. I brought this up to the host, which their response was as follows:
"It's not hydrogen sulfide gas, it's from the plumbing itself that is old The smell you feel is the smell of the sewer, sorry about it But in this building we can't do anything.. I recommend you to put as hot water as possible running in the shower, to help improve the smell"
According to the US Occupational Safety and Health Administration, Hydrogen sulfide (also known as H2S, sewer gas, swamp gas, stink damp, and sour damp) is a colorless gas known for its pungent "rotten egg" odor at low concentrations. It is extremely flammable and highly toxic.
Airbnb offered to move us but we could not move units easily as we had 3 full size suitcases up to 30kg, 1 oversized sports bag 23kg, 2 carry ons, a PC workstation, a dog and a full size dog crate on top of feeling nauseous. We ended up checking out early but it took some time to slowly move our things. Host also says that no other guests had complained, as if to discredit our complaint.
They requested to come to the unit twice, they did not give a reason for the visit since they said they could not do anything about the problem. One request was on one of the two days where the wifi in the building was out, the other time I was feeling sick in bed for most of the day and was not available.
This building should not be deemed safe for habitation.