What type of water sources are you planning to get drinking water from? There are many manmade ponds and lakes located around cities, planned communities and golf courses. I know people who feel that they can use this water.
However, many of these ponds have big lawns or exotic plants around them. In the southwest and other parts of the country, you see trees that are not native to the area by the ponds. These trees and lawns take a lot of maintenance. This results in heavy use of chemical fertilizers and toxic pesticides, especially around golf courses. The runoff collects in these ponds or lakes. If you are planning to use one of these sources for your water, you may want to check and find out what chemicals are being used nearby.
A tip for people who live or travel in urban areas during an emergency. If the water is still on carry a pair of pliers, (I carry a Leatherman Wave) many of the outdoor water spigots will have their handles removed. This is commonly done to keep people from turning them on.