9. Depth to ground water at both house and field where sewage is to be distributed.
10. Minimum winter temperature and approximate depth to which frost goes.
11. Number and kind of buildings to be connected with the sewer.
12. Number and kind of plumbing fixtures in each building.
13. Whether plumbing fixtures are to be put in the basement.
14. Depth of basement floor below ground.
A plan to scale or a sketch with dimensions showing property lines, buildings, wells, springs, and drainage outlets should be furnished. The direction of surface drainage should be indicated by arrows. The slope of the land (vertical fall in a stated horizontal distance) should be given or if possible a contour plan (showing lines of constant elevation) should be furnished.
GREASE TRAPS.
Farm sewage may contain from 10 to 30 pounds of grease and fats per person per year. This grease, originating mainly in the kitchen sink, hinders septic action and clogs pipes, filters, and soils. Half the grease may be stopped by a septic tank, but the remainder goes into the distribution system, interfering with its action. A grease trap is a device for separating the grease from other wastes. The need for it may be lessened by carefully depositing waste greases and fats with the garbage; but one should always be installed if the kitchen is carelessly managed or discharges quantities of greasy water as at institutions, hotels, boarding houses, and bakeshops.