Sewege smell that comes and goes in bedroom with no bathroom

My water heater is making Sulphur smelling water, and I've also been smelling a random sewege smell I'm my bedroom and on the side of my house where my bedroom is. But everytime I smell it I run to where the water heater is stored and there's no smell coming from outside the water heater. I've also had an issue with my kitchen drain smelling like Sulphur as well but that started before the water heater issue. I think it could be some sort of vent issue but I can't find any vents on the outside of my house or on the roof. Also I'm not sure if this could correlate to the problem but we had a power outage for about 2 days and the smell started in my bedroom on the first night of the power outage, anyone know what could be happening? Any advice is very appreciated