I get a mildew type odor in my basement from a sump pump hole. There is nothing that empties into it, but it is tied into our septic line in case the hole was to fill. The hole has a dirt/rock floor, so it's not concrete. After using the shop-vac to clean out all the water from the hole, I noticed water back in the hole after a large rain. I'm thinking water is coming up from the ground and sitting in this hole causing a mildew type smell. Could I put plastic down & then a 1"-2" of concrete in the bottom of the hole to prevent water from "leaching" back into the hole?
Has anyone else had a similar issue? The house is about 30 years old and we've owned it for around 6 months. The smell has always been there-sometimes worse then others. I have attached a couple pics of what the sump pump hole & waste lines look like. The washer dumps into this waste line & then it runs into a main discharge that runs to the septic system (just the other side of the hot water heater).