What does water with warm water mean? Does room temperature qualify? What is the best way to test for acid in rainwater?

Room temperature water somewhere around 65 degrees is is fine for most plants. If you take water from your tap at the time of watering do the finger test were it should feel cool almost unnoticable to the touch but not hot or cold. cold water shocks the plants root system and hot water over 85 degrees can cook them. A PH test kit can be purchased at any home improvement store or at a pet shop that has fish and costs about $10.