This past spring, we had an unfortunate incident in our basement where our sump pump hose froze after we prematurely reconnected the extension hose that takes the water to the yard. The pipe froze up one night, causing a huge backup in our sump pit, which caused flooding in our basement. Meanwhile, we had been noticing a strange odour coming out of our sump pit all winter (it's our first year in the house). It turns out that the main sewer line was totally clogged with tree roots. Therefore, the flood that occurred in our basement had sewage mixed in. Anyway, the mess was cleaned up, carpets stripped, drywall in affected areas replaced, etc. Most importantly, we got the roots cleaned out of the sewer line that connects to our house. Even the basement toilet was finally flushing properly, so the root cleaning seemed to solve a lot of problems.
We were holding off on re-carpeting the basement just to make sure that everything was clean. Then, about a month later, a very strange smell was developing in one corner of the basement - it wasn't mould, it was kind of had a rotten smell. We waited a few days because we thought we were just paranoid, but eventually you could smell it upstairs. We went down to inspect the area closer, and noticed that there were small chunks of rubber/foam, from the carpet underlay, which had been left behind from the previous carpet being stripped. They were tiny chunks but they were infested with that strange smell, and seem to have been causing the problem.
We just scraped the floor as much as possible, mopped with a bleach solution, and that seemed to take care of it. It was good for a couple of weeks; then about two months ago, the odour came back for good. With fall here, there has been a slight improvement, but the odour lingers. We have been told by a plumber that there is a possibility that the sewage, which had been sitting for so long, has infested the weeping tiles, or floor in some way. It was suggested that we flush our weeping tiles with a hose. This plumber ensured us that we could probably just do it ourselves and we tried, but it hasn't been very successful. Are the services of a professional recommended for this? Is there special equipment involved, after all? Is there a possibility that our weeping tiles and/or foundation are permanently infested and/or ruined?
Any suggestions would be great.
Your question brings up a regular concern seen during my home inspections. That is not removing a sump pump extension hose before winter. Just this week, I inspected a home in a newer area where the sump pump extension hose, sitting in the yard, was frozen solid. When the sump pump turned on and attempted to pump out some melted snow that accumulated in the sump pit from the weeping tiles, it was unable. The pump stayed on for more than 10 minutes before I unplugged it and went outside to disconnect the frozen line. About a minute after the pump was plugged back in, the water was cleared from the pit and the pump shut down.
In this case, the hose was properly connected with a simple pipe clamp that was easily unscrewed and the extension hose removed. Many homes have a more difficult arrangement, or underground extension pipes. These must all be disconnected in the fall, once the weather drops below freezing, to prevent burnout of the sump pump and similar backup problems to those that you have experienced. A few discharges from the short pipe sticking through the foundation, during moderate weather, will cause little if any harm to the house.
From the information you have given me about the tree roots in your sewer line, I am assuming that you live in an older home, in an older area. New areas do not have these problems as the plastic drains underground are not subject to tree route intrusion, and there are few large trees. I can also assume that the sump pit and pump in your home was not original, and was installed later. These are normally installed as a safety device to remove weeping tile water, in case of a blocked sewer or backup, during heavy rains. They do not normally operate unless this series of events occurs, or if the old weeping tiles have been routed into the new pit.
The sump pit, in this style of installation, is often connected to the floor drain catch basin with an overflow pipe. Water should only go into the pit, if the catch basin overfills. This may have happened regularly if the sewer was partially blocked by tree roots. In this case, sewage may have backed up into the weeping tiles and may also have been pumped outside with the sump pump.
The smell may be due to sewage in the weeping tiles, as the plumber suggested, or may simply be due to moisture in the weeping tiles or in the framing and wall coverings in the basement. If the smell is from a corner of the basement, away from the floor drain, then the backup may have made the walls in the basement wet, and removal of damaged material may be required. The smell may also be due to the weeping tiles having been filled with water, and possibly sewage, for a long time. It may take a long time for the damp weeping tile to dry enough for the smell to go away. Heavy rains and snowmelt runoff may extend this drying. Flushing the weeping tile with warm, soapy water, repeatedly, may be the only solution. I don’t know any professionals that do this regularly, although some Roto-Rooter companies may provide this service. Caution must be exercised, as clearing the weeping tiles with the rooter, such as was done in the main drain, is not recommended due to brittle nature of old weeping tile.