The most effective way to deal with mold is to prevent water from entering the building envelope. Given that this is impossible sometimes as leaks can occur no matter what you do, but be aware of potential roof leaks as well as leaking from plumbing fixtures. Preventative steps should be taken, so look and take necessary action.
Also, remember that exterior walls are not equipped to sustain the prolonged direct impact of water. That can break down the moisture shield causing water intrusion into wall cavities. This can happen due to sprinkler water spraying directly onto the wall, but it can also occur due to prolonged rainy periods with the wind causing an impact on a particular wall.
Once water intrusion does occur, remedies need to be applied as soon as possible. The source of the water must be determined and eliminated at the source as possible. During El Nino, wind- driven rainwater impacting on a wall might require a barrier to limit that impact.
Keep in mind that any sort of roof repair or other actions to keep rainwater from the building envelope is likely to be more difficult to obtain and more expensive due to the increased demand. So take whatever preventative actions possible now.