Sink and shower drains are some of the busiest pipes in the house. These pipes carry waste or used water from the house to the sewer system. In other words, they connect the house with the underground sewer system. This means that all that human waste and other liquid waste that flows in your home sewer system are accessed by the drain pipes. And because this waste is quite smelly, you can expect this foul smell to waft through the drain pipe back into the house. But indoor plumbing is amazing. Plumbing technicians invented a simple solution to keep this smell from coming back up. It's called the drain trap. This is the u-shaped bend that you see in any drain pipe. Because of its shape, the drain trap always holds some water and this water acts as a barrier preventing the bad odors from wafting back into the house. But these foul smells sometimes find a way of getting back into the house despite the presence of the water trap. If you detect a foul smell coming out of your drains, then it could be caused by several factors and we are going to discuss all of them below and how they can be fixed.
If you do not use a sink, shower, or even urinal for a very long time, then all the water in the drain trap can evaporate and leave the drain trap open. Remember that this water is the only thing keeping the foul smells from the sewer system from coming back into the house. When all the water in the drain trap is gone, you will start smelling your sewer system from inside your house. You can easily fix this problem by running some water in your sink, shower, or urinal. Leave a tap or shower running for some time and then close it. Make a point of doing this when you have stayed for too long without using a certain sink or shower. Some of the water will remain in the drain trap and the foul smells will be kept at bay.
Sometimes the bad odors won't go away even when you fill the drain traps. Actually you can notice bad odors coming from a sink drain trap that you use regularly. This means that there is no problem with the drain trap. It could be a problem with smelly bio-film coating the inside of the drain pipe. You will have to clean that drain pipe manually to get rid of the stinky smell. You can detach the drain pipe and use a long flexible brush to clean the inside. Use a chemical an all-natural drain cleaner or buy a chemical bleach and water to clean the smelly drain pipe.
If the foul smell is coming from multiple drains in the house, then you have a much bigger problem. You will need to call a professional plumber who provides DC drain cleaning services to diagnose the problem. You can also call the local sewer authority because the problem could be on their end. The problem could be in your home sewer system or it could be originating from the municipal sewer system.