A septic tank-soil absorption system under favorable environmental circumstances is a satisfactory method of residential sewage disposal. Under unfavorable environmental circumstances and if carelessly designed and constructed, such systems are a source of embarrassment and expense to the home owner as well as a problem to the authorities. Soil absorption systems have apparently resulted from a gradual evolution from a privy, to a cesspool, to a seepage pit and to a trench type system. The report discusses the testing and problems of soil absorption.