We have purchased a beautiful piece of property in an "equestrian themed" professional subdivision with estate sized lots on which we intend to build our dream home. The subdivision is in the very early stages of marketing and, although several homes are under construction, no one lives there yet. We fell in love with the land and the surrounding area at first site. Our lot is bordered on two sides by heavily wooded county park land and the subdivision is in a valley between two ridges (low lying area). However, all assays indicate that no part of the subdivision is in a flood plane. Back in the woods behind our lot, there is a fairly well concealed concrete building which is a sewer metering station. There are a number of these little "stations" within several miles. We have been told that these are checked very often and that they also could not leak gas.
Shortly after signing the contract to purchase the lot, we were out on our lot one hot, still, muggy evening. Very typical weather for July and August here in the midwest. That evening I noticed an odor as I walked around on the property. It was a smell somewhat akin to sewer gas, but not nearly so foul. It did smell like some type of gas leak. I immediately suspected that it was leaking from a sewer metering station. I have since been assured that is not the case. Since that time we have been there numerous times and the odor has been very strong. It occurs mainly in the evening, but not always, when it is very still (little to no breeze) and hot. The developer, a very honest and highly educated man suspects some sort of gas coming through the ground. There is no sewer treatment plant within miles. There is a small river approximately 1/4 a mile back into the woods behind the property. If there is even the slightest breeze, the smell is not there.
It has been suggested that this is methane escaping from leaky sewer pipes that the developer tapped into. However, I do know that methane is a colorless, odorless and highly flammable gas. That does not fit the description of our gas smell.
It is our great desire to build on that lot, but we need to know if there are any possible health or safety hazards from building there and "what in the world could this smell possibly be coming from". We could get used to a little odor for short periods of time (from time-to-time), but if it puts my family at risk, I would not want to keep the lot.
Does anyone have suggestions about what this could be and/or how it might be gotten rid of? Is there an official department I could call for help with testing. (i.e. EPA etc.? Could it come through the basement walls or floor in the future and thus pose a health risk?