Musty odors in the living area
As much as 50% of the air upstairs comes from below - this means mold spores, musty smells, and humid air that dust mites love.
Condensation on insulation, water pipes
While a footing drainage system can be effective for a time, eventually muddy water and particles enter the pipe and reach a tipping point. At this point, drainage is limited or completely obstructed. If the tiling comes into the home the sump pump plays a huge part in keeping your basement dry. Typically homes have builder grade sump pumps that are not very effective. All sump pumps are mechanical and will fail and some point
Mold
Mold loves moisture. And mold loves to eat dead organic materials, like wood, paper, and cardboard. The bad news is most crawl spaces have lots of moisture, as well as wood and other organic materials for mold to grow on.
Rot in Wooden Framing
The clay bowl effect refers to the natural consequence of excavating and backfilling when building a foundation. Water in the soil close to the foundation can and will build up and find its way in, seeping through porous basement walls or through gaps and basement wall cracks. Sometime when you first get water in your basement it comes in one section of the basement but due to the clay bowl effect the water pressure is around your entire foundation
Insect Infestations
Dust mites thrive in humid environments, so they love homes with a dirt crawl space underneath. Dust mites are microscopic parasites that live in your bedding, carpet, and furniture. Dust mite droppings float in the air and can trigger allergies and asthma. Other pests, like termites, spiders, mice, rats, and snakes love damp, dirt crawl spaces too
Buckling Wood Floors
A home with a dirt crawl space costs more to heat and cool. The reason for this is damp air takes more energy to heat or cool and more energy used means higher energy bills.