Building zone laws are of modern origin. They began in this country about twenty-five years ago. Until recent years, urban life was comparatively simple; but with the great increase and concentration of population, problems have developed, and constantly are developing, which require, and will continue to require, additional restrictions in respect of the use and occupation of private lands in urban communities. Regulations the wisdom, necessity and validity of which, as applied to existing conditions, are so apparent that they are now uniformly sustained a century ago, or even half a century ago, probably would have been rejected as arbitrary and oppressive. Such regulations are sustained, under the complex conditions of our day, for reasons analogous to those which justify traffic regulations, which, before the advent of automobiles and rapid transit street railways, would have been condemned as fatally arbitrary and unreasonable. And in this there is no inconsistency, for, while the meaning of constitutional guaranties never varies, the scope of their application must expand or contract to meet the new and different conditions which are constantly coming within the field of their operation. In a changing world, it is impossible that it should be otherwise. But although a degree of elasticity is thus imparted not to the meaning, but to the application of constitutional principles, statutes and ordinances which, after giving due weight to the new conditions, are found clearly not to conform to the Constitution of course must fall.
The ordinance now under review, and all similar laws and regulations, must find their justification in some aspect of the police power, asserted for the public welfare. The line which in this field separates the legitimate from the illegitimate assumption of power is not capable of precise delimitation. It varies with circumstances and conditions. A regulatory zoning ordinance, which would be clearly valid as applied to the great cities, might be clearly invalid as applied to rural communities. In solving doubts, the maxim sic utere tuo ut alienum non laedas, which lies at the foundation of so much of the common law of nuisances, ordinarily will furnish a fairly helpful clew. And the law of nuisances likewise may be consulted not for the purpose of controlling, but for the helpful aid of its analogies in the process of ascertaining the scope of, the power. Thus, the question whether the power exists to forbid the erection of a building of a particular kind or for a particular use, like the question whether a particular thing is a nuisance, is to be determined not by an abstract consideration of the building or of the thing considered apart, but by considering it in connection with the circumstances and the locality. Sturgis v. Bridgeman, L.R. 11 Ch. 852, 865. A nuisance may be merely a right thing in the wrong place -- like a pig in the parlor instead of the barnyard. If the validity of the legislative classification for zoning purposes be fairly debatable, the legislative judgment must be allowed to control. Radice v. New York, 264 U. S. 292, 264 U. S. 294.
There is no serious difference of opinion in respect of the validity of laws and regulations fixing the height of buildings within reasonable limits, the character of materials and methods of construction, and the adjoining area which must be left open, in order to minimize the danger of fire or collapse, the evils of over-crowding, and the like, and excluding from residential sections offensive trades, industries and structures likely to create nuisances. See Welch v. Swasey, 214 U. S. 91; Hadacheck v. Los Angeles, 239 U. S. 394; Reinman v. Little Rock, 237 U. S. 171; Cusack Co. v. City of Chicago, 242 U. S. 526, 242 U. S. 529-530.
Here, however, the exclusion is in general terms of all industrial establishments, and it may thereby happen that not only offensive or dangerous industries will be excluded, but those which are neither offensive nor dangerous will share the same fate. But this is no more than happens in respect of many practice-forbidding laws which this Court has upheld although drawn in general terms so as to include individual cases that may turn out to be innocuous in themselves. Hebe Co. v. Shaw, 248 U. S. 297, 248 U. S. 303; Pierce Oil Corp. v. City of Hope, 248 U. S. 498, 248 U. S. 500. The inclusion of a reasonable margin to insure effective enforcement will not put upon a law, otherwise valid, the stamp of invalidity. Such laws may also find their justification in the fact that, in some fields, the bad fades into the good by such insensible degrees that the two are not capable of being readily distinguished and separated in terms of legislation. In the light of these considerations, we are not prepared to say that the end in view was not sufficient to justify the general rule of the ordinance, although some industries of an innocent character might fall within the proscribed class. It cannot be said that the ordinance in this respect "passes the bounds of reason and assumes the character of a merely arbitrary fiat." Purity Extract Co. v. Lynch, 226 U. S. 192, 226 U. S. 204. Moreover, the restrictive provisions of the ordinance in this particular may be sustained upon the principles applicable to the broader exclusion from residential districts of all business and trade structures, presently to be discussed.
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The decisions enumerated in the first group cited above agree that the exclusion of buildings devoted to business, trade, etc., from residential districts bears a rational relation to the health and safety of the community. Some of the grounds for this conclusion are promotion of the health and security from injury of children and others by separating dwelling houses from territory devoted to trade and industry; suppression and prevention of disorder; facilitating the extinguishment of fires and the enforcement of street traffic regulations and other general welfare ordinances; aiding the health and safety of the community by excluding from residential areas the confusion and danger of fire, contagion and disorder which, in greater or less degree, attach to the location of stores, shops and factories. Another ground is that the construction and repair of streets may be rendered easier and less expensive by confining the greater part of the heavy traffic to the streets where business is carried on.
The matter of zoning has received much attention at the hands of commissions and experts, and the results of their investigations have been set forth in comprehensive reports. These reports, which bear every evidence of painstaking consideration, concur in the view that the segregation of residential, business, and industrial buildings will make it easier to provide fire apparatus suitable for the character and intensity of the development in each section; that it will increase the safety and security of home life; greatly tend to prevent street accidents, especially to children, by reducing the traffic and resulting confusion in residential sections; decrease noise and other conditions which produce or intensify nervous disorders; preserve a more favorable environment in which to rear children, etc. With particular reference to apartment houses, it is pointed out that the development of detached house sections is greatly retarded by the coming of apartment houses, which has sometimes resulted in destroying the entire section for private house purposes; that, in such sections, very often the apartment house is a mere parasite, constructed in order to take advantage of the open spaces and attractive surroundings created by the residential character of the district. Moreover, the coming of one apartment house is followed by others, interfering by their height and bulk with the free circulation of air and monopolizing the rays of the sun which otherwise would fall upon the smaller homes, and bringing, as their necessary accompaniments, the disturbing noises incident to increased traffic and business, and the occupation, by means of moving and parked automobiles, of larger portions of the streets, thus detracting from their safety and depriving children of the privilege of quiet and open spaces for play, enjoyed by those in more favored localities -- until, finally, the residential character of the neighborhood and its desirability as a place of detached residences are utterly destroyed. Under these circumstances, apartment houses, which in a different environment would be not only entirely unobjectionable but highly desirable, come very near to being nuisances.
If these reasons, thus summarized, do not demonstrate the wisdom or sound policy in all respects of those restrictions which we have indicated as pertinent to the inquiry, at least the reasons are sufficiently cogent to preclude us from saying, as it must be said before the ordinance can be declared unconstitutional, that such provisions are clearly arbitrary and unreasonable, having no substantial relation to the public health, safety, morals, or general welfare. Cusack Co. v. City of Chicago, supra, pp. 242 U. S. 530-531; Jacobson v. Massachusetts, 197 U. S. 11, 197 U. S. 30-31.
