If you feel that your neighbor might be running afoul of your local zoning rules and regulations, and that the zoning ordinance is not being enforced, contact your local zoning and planning office or city attorney’s office. Ask them to explain the matter to you. The complaint process varies enormously among municipalities. In some areas, there are complaint forms; in a few, a complaint can be emailed. In most cases, a reported complaint is followed up by an inspection. Having the city take up the enforcement campaign is a lot cheaper way to start than initiating a lawsuit.