The restriction can be found in the Declaration and General Protective Covenants for Gateway Greens Community, Section 3.11.
Accessory Structures. "No accessory structures (i.e. playhouses, swing sets, tool or garden equipment sheds, basketball hoops, game courts, doghouses, barbecues or like structures) unless approved. Soccer nets, hockey nets and other portable play equipment shall be stored in garages or other approved storage areas overnight and when otherwise not in use."