Geomancer: How long do terrain attunements last?

[Cyrad]

Most of the terrain attunements listed in the Geomancer archetypes.

When I gain an attunement, how long do they last? Do I keep them even when I leave the corresponding terrain?

If I go with RAW, it seems that when I cast a water spell in an aquatic terrain to gain the aquatic attunement, I gain its benefits indefinitely until I cast another spell in another terrain to gain a different attunement.

[Cordell Kintner]

Water is the only one without an explicit time limit. I would think the issue is with that attunement, not with the rest of the ability.