Are you allowed to put up a swimming pool without a fence?

From Guardian Pool Fence

When one is planning a swimming pool project in one's backyard, most homeowners assume that they will have to put up a self-closing, self-latching gated fence around the pool.  What these people in some instances find out is that either the fence ruins the aesthetic that they are trying to achieve, or the municipality doesn't necessarily require a fence.  This post from Guardian Pool Fence addresses the issue head-on, and attempts to argue that even in municipalities in which a fence isn't required, it is still a necessary protection for the homeowner and his neighbors.