The board is not waterproof. We’ve made several design decisions to make it as water resistant as possible. You can ride through irrigation runoff or the occasional puddle, but we don’t recommend riding in wet conditions - not when it’s raining or right after it has rained - as you may damage the electronics and rust the bearings. Also it’s extremely dangerous to ride in conditions with reduced traction, both for your board AND because of the cars around you.
The battery box is fully sealed, and partitioned to seal battery compartment and motor controller compartments independently. We chose sensorless motors to further reduce susceptibility to water, and made many components easily serviceable for regular maintenance.