All above-ground 24 inches in height and over and in-ground pools must have a building permit. These also include the inflatable pools.
There are specific requirements for location, fences, gates, locks, and electrical regulations for a pool Above ground pools with at least 48" between pool top and adjoining grade do not need a separate barrier (fence) if the only access to the pool is by a ladder or steps either shall be capable of being secured, locked or removed to prevent access or surrounded by a barrier (fence). Decks attached to pools must meet the barrier requirements.
In-ground and above-ground pools over 24 inches in height (including inflatable pools) are required to have a barrier around them. A four-foot fence must be installed around with a self-closing and self-latching gate. See code section 3109 that covers swimming pool enclosures. There are also specific requirements for electrical installations for pools. See code requirements for electric.
Remember that pools cannot be erected below electrical power lines or on any easements on your property.