Most notable is a study of 20,000 Seventh-Day Adventists, who were followed for six years to look for impact of fluid intake on mortality. The researchers found that drinking more water lowered the risk of dying. For women, the risk was lowered by having three or more cups per day, versus fewer than three. For men, three to four cups was much better than fewer than three, and five or more cups was a bit better than that. And at least one study has found that more than six cups of water a day lowers bladder cancer risk relative to less than one cup.
One gallon is about 128 ounces, so if one tea bag is good for 10 oz  of water, then about 10 teabags is good for a gallon. Start with 10  and adjust accordingly with water. 4 people found this useful.
At first glance, loose leaf tea seems more expensive because the price of the bag on the shelf may be $8, and you know at the grocery store there are boxes of tea for $2.50. The box of tea at the grocery store probably has 20 bags of tea, about 12.5Â¢ per cup of tea. The loose leaf tea says 3 oz. As we will discuss below, the rule is to use 2 grams of loose-leaf tea per cup. There are about 85 grams in 3 oz, so there are 42.5 cups of tea in a 3 oz. loose-leaf package. The loose-leaf will be around 19Â¢ per cup of tea, just 5Â¢ more for much better quality. The only thing to stop you now is the convenience of tea bags.