When we do laundry the house gets an odor. Not a septic odor but an almost stagnant water smell. We just had our septic tank replaced. What could be causing this?

Why was the septic tank replaced ? Did it back up ?

It never backed up into the house. The cap was removed and it was spilling onto the yard. One other thing I might add. The laundry room, one bathroom and the kitchen sink are all in proximity. And ever since we lived in that house those drains make a gurgling sound when we do laundry. I'm thinking that there may not be a vent pipe or if it does have one that it may be clogged. Is that a possability?

Not related to your septic but is related to proper venting. The gurgling noise you hear is air venting itself through your traps. Your vent stack exits on your roof, rod from there with enough 1/2" snake to rod roof to basement floor plus 15'.

Thank You ballengerb1!. Could the smell be caused by the "S" pipes being voided of water during the gurgling process? I would think that this would make the "S" trap open to the drain line causing the smell.

The trap usually never gets totally void and if it did the sewer gas would not be mistakeable. The trap mostly burps some bubbles of air so the smell is a bit less severe.