Waterproofing is usually required by building codes for structures that are built at or below ground level. Waterproofing and drainage considerations are especially important in cases where ground water is likely to build up in the soil or where there is a high water table.

Water in the soil causes hydrostatic pressure to be exerted underneath basement floors and walls. This hydrostatic pressure can force water in through cracks, which can cause major structural damage as well as mold, decay, and other moisture-related problems.

Several measures exist to prevent water from penetrating a basement foundation or to divert water that has penetrated a foundation:

● Interior wall and floor sealers
● Interior water drainage
● Exterior drainage
● Exterior waterproofing coatings
● Box type waterproofing
● Foundation crack injections.

Water seepage in basement and crawl spaces usually occurs over long periods of time and can be caused by numerous factors.

Concrete is one of the most commonly used materials in home construction. When pockets of air are not removed, or the mixture is not allowed to cure properly, the concrete can crack, which allows water to force its way through the wall.
Foundations (footings) are horizontal pads that define the perimeter of foundation walls. When footings are too narrow or are not laid deep enough, they are susceptible to movement caused by soil erosion.

Gutters and downspouts are used to catch rain water as it falls and to discharge it away from houses and buildings. When gutters are clogged or downspouts are broken, rainwater is absorbed by the soil near the foundation, increasing hydrostatic pressure.