Utah Supreme Court
552 P.2d 136 (1976)
Estoppel, waiver or laches ordinarily do not constitute a defense to a suit for injunctive relief against alleged violations of the zoning laws, unless the circumstances are exceptional.
Zoning ordinances are governmental acts which rest upon the police power, and as to violations thereof any inducements, reliances, negligence of enforcement, or like factors are merely aggravations of the violation rather than excuses or justifications therefor.
Ordinarily a municipality is not precluded from enforcing its zoning regulations, when its officers have remained inactive in the face of such violations.