The septic tank system in suburbia.

THE WIDESPREAD use of the septic tank has come as a result of an unprecedented demand for housing in suburban areas. Before attempting an evaluation of the septic tank as a means of sewage disposal, it is well to review the factors promoting its use. Since the septic tank is intimately connected with the house-building industry, the review must consider that industry and the forces governing its activities. After a long freeze during the war, construction got under way in the late 1940's with a mass movement of people to the suburbs of population centers. It seemed reasonable at that time to believe that this shift in population resulted from the wartime backlog of housing demand, that eventually construction would catch up with demand leaving relatively stable communities with new outer boundaries, and that permanent facilities could then be installed to replace the temporary devices used during the expansion period. It now appears that this reasoning was in error. The tremendous increase in the birth rate following the war was contrary to all predictions. In 1940, the consensus was that the population of the United States had become relatively stationary and perhaps would even begin to decline. Even as late as 1946 a population of 153 million was forecast for 1960, and an ultimate peak of 164.5 million was predicted for 1990. The great increases in marriages and births following the war made these predictions appear ridiculous. The present population is more than 171 million, and an estimate of 180 million now seems logical for 1960. In fact, during the past 10 years population increase has consistently exceeded the estimates. The number of immediate housing starts is more nearly associated with new family formation than with population increase. The formation of new families is sagging at present. One reason may be that people of marriageable age are now being drawn from the low birth rate years of the depression, but the high birth rate after the war should bring a population wave in the marriageable age commencing in the late 1960's. Even now we are watching a wave of children pass through grade school. In a few years they will be in high school, later in college, and then they will marry and become prospective home owners. Family income is another factor that greatly influences house building and home ownership. In spite of increases in the cost of housing, rising family income has brought home ownership within the reach of a large portion of the Nation. The percentage of owner-occupied dwellings rose from 43.6 percent in 1940 to 55 percent in 1950, and a further increase to 60 percent is predicted for 1960 (1). There is also Mr. Coulter is senior sanitary engineer, Suburban Sanitation Studies, at the Public Health Service's Robert A. Taft Sanitary Engineering Center in Cincinnati, Ohio.