Take a break from swimming in the usual spot at Kamogawa, and head north towards the mountains. The very first car-accessible bridge you come across, cross over Kamogawa and you will see signs for Tsugoe Waterfall. Although many locals come here to swim, you can expect to find a private place to enjoy the peaceful quiet of nature. The signs lead to the parking lot, from there follow the river on its west side through the neighborhood for about a minute, before it leads you to a very clear, paved path into the woods.
This is a place I've been to about a dozen times. Officially, however, this waterfall is closed to tourists after the footbridge crossing over the river to the waterfall collapsed. Its very easy to cross the river just a few dozen yards before where the old bridge used to be. Even if you decide to descend to the river from the high (2m) bank where the bridge once stood, any novice climber can find their way with no trouble. There are also several smaller waterfalls with swimming pools that can be seen along the walk prior to Tsugoe falls.