PREPARATORY MAPS AND DATA 29 



capita rates or volume of sewage to be provided for; the allowance, if any, 

 for storm- or roof-water, and the full reasons for the inclusion of such 

 water in the system. The report should include a description of all con- 

 ditions peculiar to the locality, affecting in any way the design of the 

 system; a description of all special devices used in the design and of any 

 special points to be observed in the maintenance and operation of the 

 system. The report must contain a full description of the general arrange- 

 ment and all special features of the proposed sewage-disposal works, the 

 reasons for the choice of the method or type proposed and a full description 

 of the proposed operation of the plant. A full statement must be given 

 of the capacities of the various parts of the works, the population which 

 works are designed to serve and the reasons for any unusual capacities 

 adopted. 



7. General Requirements. (a) All plans, specifications and reports 

 must be submitted in duplicate, and the application for approval must 

 be submitted on blanks issued by the Department for the purpose and 

 signed by the proper municipal authorities or their properly authorized 

 agent (in the latter case a letter of authorization must accompany the 

 application). If approved, the original set will in general be returned 

 and the duplicate set, if clear and distinct prints, on suitable paper or 

 cloth, will be filed with the Department according to law. 



(6) In general, and except in certain restricted districts and for very 

 cogent reasons, the Department will approve of plans for new systems 

 only when designed upon the "separate" plan, in which all rain-water 

 from roofs, streets and other areas, and all ground- water other than 

 unavoidable leakage and a very restricted allowance for cellar drainage, 

 shall be excluded. When plans for the extension of "combined" sewers, 

 already built and in operation in full accordance with the provisions of 

 the Health Law, are submitted, approval will in general be given only in 

 cases where the district tributary to the sewer extension is of limited 

 area and cannot be included in a new and distinct sewer district con- 

 struction upon the" separate" plan. 



(c) The Department will in general approve only of plans which include 

 disposal works for such complete purification as will produce a clear and 

 "stable" effluent. If it is proposed to omit certain portions of these 

 works for the complete purification of the sewage, there must be shown 

 upon the plan a reserve area and the general arrangement of the type, 

 methods and devices which it is proposed to instal in the future when 

 such complete works are required; and included in the engineer's report 

 the full reasons why any of such portions of the complete works are tem- 

 temporarily omitted. 



(d) The approval of the Department is not required by law for drams 

 designed and used exclusively for storm-water, subsoil-water and for other 



