The proper amount of bleach to add to your fresh water to preserve it's freshness leaves you with approximately 1ppm free available chlorine residual. Because there are many variables that changes the chlorine demand, you should get a pool test kit to determine your residual. 1ppm free available chlorine residual is the desired amount in a swimming pool. Most municipal water districts like to see about .4-1ppm free available chlorine residual in the water that they put into the public water lines when it leaves the plant.