I am a professional photographer and was turned onto this waterfall by a local tour company which took hikers up to Likeke waterfall on a daily basis.
There are a number of companies who do this.
The easier way to get up to the falls is from below through the Koolau Golf course. As people drive into the golf course the club house can be seen to the right with the parking lot straight ahead. Instead of turning right, stay left and park as far away from the club house as possible. The beginning of the path is there through a maintenance road to a water catchment tank.
Just before the tank is a path on the left that will take people up to the falls. It is only a 15 – 20 minute hike and some of the stretches can be a little steep but safe. As we walk the path it will remind people of the scene in Indiana Jones where the round boulder chased after Indy.
About 10 minutes up the path we hit the stone road and almost immediately to the right is the large opening to the trail that will take us up to the falls. This will be the muddiest and steepest part of the hike but still easy to walk.
Once up to the waterfall the path continues on for a few miles to the Hoomaluhia Botanical Gardens. The falls are beautiful and have multiple levels that include two small pools. The falls themselves are much higher than 15 feet, however.