There are two types of differing site conditions; Type I and Type II.

To recover for a Type I differing site condition, a contractor must prove that:

1. The contract indicated a particular site condition;
2. The contractor reasonably interpreted and relied on the indications;
3. The contractor encountered latent or subsurface conditions which differed materially from those indicated in the contract; and
4. The claimed costs were attributable solely to the differing site conditions.

To recover for a Type II differing site condition, a contractor must prove that:

1. The conditions encountered were unusual physical conditions unknown at the time of contract award; and
2. The conditions differed materially from those ordinarily encountered.

The contractor must prove its differing site conditions damages.