The ultimate goal in construction is zero water intrusion, and they're not using treated wood. This seems counter-intuitive. Why would you expose framing lumber to water?
The answer is simple: limited water exposure will not hurt the wood.
Water will inevitably destroy wood. Wood is porous and will readily absorb water like a sponge, causing it to expand. Sooner or later, the water will evaporate and the wood will shrink back down. It's this constant process that will inevitably destroy even pressure-treated wood. It's why waterproofing on a regular basis will extend the life of the wood.
How do builders get away with this without pressure-treat or waterproofing? It takes months (or years) for this process to take hold, and typically the framing and OSB are only exposed for a few weeks at most. Watch the color of the wood. The yellowish color fading to grey is the first sign that water damage is happening. I bet none of the wood even fades a little before they enclose the walls and put a membrane on the roof.
What about termites? Termites need for the wood to remain wet for them to dwell there. Remove the water and the termites will usually move on in short order. The rain won't last forever and the finished house should not provide them any water sources.
