It's amazing that you can live in an area for a number of years and not know that a 15 minute drive from your house is a 4000 acre preserve and around 10 miles of hiking trails within that space.
One afternoon while trying to avoid freeway traffic, my husband suggested we take a back road that uses occasionally, which is not a route I had driven before, however we passed a sign and parking area to the Los Penasquitos Canyon Preserve. As soon as we got home I researched the area, and then arranged to meet with our kids to do a 6 mile hike there that weekend.
I printed out a map from the San Diego Parks & Rec website and we with drinks and snacks in our backpacks set off. This is the route we took.
Map of route via Runkeeper
At the 3 mile mark (halfway through our hike) we arrived at the waterfall. If you are thinking side of a mountain water falling, that is not what you will find here, it's more large rapids and a small drop off as you will see from the photographs below that run through volcanic rock. Our hike took us along one side of the creek, we crossed over at the waterfall and then returned to the parking lot on the other side of the creek.
It's quite a busy trail with lots of other hikers, families, cyclists, and we even spotted a horse (the rider was lovely and let the girls hop up into the saddle).
The hike is fairly easy, it's very flat along a lot of the route we took, however there were a few small hills we had to climb and there are numerous spots where you can take another small trail off the main one to make your hike a little longer, or harder.
Let's not forget the horse that made the first 3 miles worth it.
There is a small section of stairs on either side of the water, and there were lots of people crossing, kids wading in the water (mainly ours) and hikers sitting on the rocks taking in the tranquility of the area.
You can find more information and download a hiking trail map on the San Diego Parks & Rec website.