in blocks where the greater number of houses are occupied
by white persons, and vice versa. Such a prohibition, the practical
effect of which is to prevent the sale of lots in such blocks to colored
persons, violates the constitutional prohibitions against interference
with property rights except by due process of laws; and cannot be
sustained on the ground that it will promote public peace by preventing
race conflicts.[390]

Safety Regulations

As a legitimate exercise of the police power calculated to promote
public safety and diminish fire hazards, municipal ordinances have been
sustained which prohibit the storage of gasoline within 300 feet of any
dwelling,[391] or require that all tanks with a capacity of more than
ten gallons, used for the storage of gasoline, be buried at least three
feet under ground,[392] or which prohibit washing and ironing in public
laundries and wash houses, within defined territorial limits, from 10
p.m. to 6 a.m.[393] Equally sanctioned by the Fourteenth Amendment is
the demolition and removal by cities of wooden buildings erected within
defined fire limits contrary to regulations in force at the time.[394]
Nor does construction of property in full compliance with existing laws
confer upon the owner an immunity against exercise of the police power.
Thus, a 1944 amendment to a Multiple Dwelling Law, requiring
installation of automatic sprinklers in lodginghouses of nonfireproof
construction erected prior to said enactment, does not, as applied to a
lodginghouse constructed in 1940 in conformity with all laws then
applicable, deprive the owner thereof of due process, even though
compliance entails an expenditure of $7,500 on a property worth only
$25,000.[395]

THE POLICE POWER

General

According to settled principles, the police power of a State must be
held to embrace the authority not only to enact directly quarantine[396]
and health laws of every description but also to vest in municipal
subdivisions a capacity to safeguard by appropriate means public health,
safety and morals. The manner in which this objective is to be
accomplished is within the discretion of the State and its localities,
subject only to the condition that no regulation adopted by either shall
contravene the Constitution or infringe any right granted or secured by
that instrument.[397]

Health Measures

Protection of Water Supply.--A State may require the removal of
timber refuse from the vicinity