Campo Agua is a 30 to 45 minute ride south of the city proper. Once you reach central Toril, it's 5-10 minutes further south and to the left side of the national highway. Turn left at the dirt road until you find a Talisay tree-shaded open parking. Your entrance is there. They charge PhP60 if you plan to do some swimming or have your meal in one of the cottages. Except for a mixed race couple (a mature Caucasian guy and his wife), no one else was there so I had the place pretty much to myself.
For specific queries, please google for their phone number and contact them.