When something is off with your drains and your water, your nose will let you know. It’s very common for homeowners to experience unpleasant, musty or sulfuric smells originating in their drains on in their water.
While you may not be a trained plumber, a little investigative work can help you determine what is causing these smelly problems; you can also decide if you can take care of the problem yourself or if you need professional back up.
Locate the P-Trap
The P-trap may sound complicated, but it is easy to find. Locate the curved part of the pipe underneath your 
bathroom and kitchen sinks. It has an important job to do.
Gases naturally come from the sewer, and they don’t smell very good. The P-trap uses a cushion of water to keep those smells from coming in your home.
If the P-trap dries out, there is no barrier, and smells can roam freely.
Your P-trap will dry out for one of two reasons: the sink hasn’t been used in a while, or the seal has broken around the P-trap.
First, figure out if the seal is broken and fix it needed. Second, run the water to refill the P-trap.
Water Heater Bacteria
If the smell has a sulfuric quality, check the water heater. The moist and damp environment will promote bacteria growth which can cause a chemical reaction with the anode rod that is inside your tank.
The rod works to keep corrosion at bay. If your heater has been off for a long time or if the temp is set too low, that can get the bacteria out of whack. Adjust the temp accordingly and replace the anode rod.
Sewer Situation
Sewer line problem smells appear everywhere in your home, but they may be strongest in the basement.
This is because if you have a compromised sewer line, sewage may be backing up around and underneath your foundation.
If you suspect this is the problem, you need to call for your plumber right away because your basement is at risk for flooding.
Don’t Forget Ventilation
Water goes through your pipes, but so do gases and air.
If the pipe isn’t properly ventilated (i.e. if there is a blockage) the smelly gases need to find another route, which is often back up through your drains.
Common blockage is caused by animal nests, debris, tree roots or sand and silt. Get your drains professionally cleaned to remove the blockage.