My dad's home has a pretty good "musty" smell. Smells just like when you wash clothes in the washer then forget about them for a day or two. Not overpowering, but noticable. No smell upstairs. Started about a month ago. House is a 2 story colonial home built on 1970. New roof, older vynal siding, new windows, etc. No basement, and it sits on a slab. Water, sewer and some HVAC lines are buried in the slab. Our family has had it for 42 years, and I have never smelled this smell before. Its been wet lately, but ive seen it worse. Contractor and I walked and inspected the exterior and interior for possible leaks- no smoking guns there. House has hardwoods in most of downstairs. (it was a terrible choice by my dad) No significant evidence of buckling or popping, but they have never quite felt right. Our current thoughts are possible water line leak in the slab or slab ducts are dirty and got moist. I put a dehumidifier there sunday. Curious to see if that helps. Dad, who would be prone to breathing issues, hasnt had any. Looking for thoughts and advice.