Hi Trippers! I just discovered a new water hike, and if there's ever a second printing of the book ... .
In the meantime:
Ein Aviel, near Binyamina, is a spring with refreshing water to chill in all year round, and is accessible by train+bus from Tel Aviv.
I combined the trip with a visit to Park Alona (Mei Kedem) https://meykedem.co.il/english/, which has an underground tunnel - with water! Bring flashlight and water shoes. Entrance fee 30shek.
Directions: Take the train to Binyamina. Use Google maps to find a bus to Moshav Amikam, then walk along the highway to Park Alona (also findable on Google Maps). I'll admit I skipped this step and took a taxi from Binyamina train station direct to Park Alona (taxi was 55shek).
After enjoying Park Alona, walk southeast along the highway until it bends sharply; continue instead straight along the green trail, and make your way to Ein Aviel. You'll run into people along the way to ask for directions, and you'll know when you reach the water by seeing people wading. Explore - walk down through the spring, and you'll find a (compact) waterfall!
To get back, wade through the water to the south bank, and make your way to the highway and to the bus stop in Aviel.
And the Tripping out of Tel Aviv hiking book is now 50% off!