Wooden siding has been around for a lot of years and is still in use
You have a leak within your walls that is causing the damage to the siding.
Dry rotting siding almost always starts from the inside out. Therefore, if your wood siding has been damaged by water and is starting to dry rot, it is a good indication to look behind the siding for signs of trouble. If you have plumbing lines in your walls, there could be a hidden leak that is creating the damage. Because these kinds of leaks are essentially hidden, you may not notice an interior wall plumbing leak for a long time. So if you do find a leak inside your walls that is affecting the wooden siding, make sure you repair the problem and check other surrounding structure features for issues.
Your gutters are not draining water away from the roof as they should.
This could easily be one of the biggest reasons wood siding will get water damaged and dry rot, but many homeowners fail to recognize the issue for being as serious as it is. If your gutters are clogged, damaged, or otherwise not pulling water from the roof down to the ground in a uniform fashion, this excess water can run in behind the siding panels and create issues with rot.
Your cleaning practices are leaving too much moisture behind the siding.
It is never recommended that you use high pressure water to clean wooden siding. If you use high water pressure for cleaning your