There are very few waterfalls in San Diego County. However, the Upper San Diego River has a few nice waterfalls that are worth a visit especially in the spring when the water is still flowing.
This particular waterfall is a short hike (about 1.5 miles round trip) from a small parking area located at a picnic area. However, one must be forewarned it may require some steep descent and a hike through patches of poison ivy.
The trailhead is located at the Inaja Picnic Area located on the 78 highway between Santa Isabel and Julian. The most obvious trail is to hike through the picnic tables and descend on any faint trail you can find to the river below. The descent is about 300 feet and only takes a few minutes. At the river you will find a series of small boulder falls not more than 5 feet drop. After relaxing here for a while, then find the faint trail along the western side of the river (more like a solid stream). Proceed to hike through the overgrown bushes and downstream for about a half mile. Gradually the bushes will open up to more chaparral. Once you can see the long valley ahead you are near the top of the falls. There are a few vantage points to see the 60 foot falls. Once can even sit on the ledge near the point of drop off. But be careful for smooth slippery rocks. This is a great spot for lunch and is free of poison ivy.
On the return trip, proceed the way you came.
There are other waterfalls along the Upper San Diego river but these can be accessed either through continuing down the river or going to another access trailhead.